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LIBRARY   OF   THE 

University  of  California. 


CIRC  UL  A  TING    B  R  A  N  C  Jf . 


taarweekjTj  W  a  week  before  the  end  of  the  term. 


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ELEMENTS 


LOGICR; 


OR 


A  SUMMARY  OF  THE  GENERAL  PRINCIPLES 


AND   DIFFERENT  MODES 


REASONING. 


BY    LEVI   HEDGE,  EL.  D. 

PROFESSOR    OF    NATURAL  RELIGION,    MORAL   PHILOSOPHY,   AND    CIVIL    FOLITr, 
IN    HARVARD    UNIVERSITY. 


STEREOTYPE    EDITION^  J  V  fg 


'4£ft 


Boston: 

PUBLISHED  BY    IIILLIARD,  GRAY  &  CO. 


1835. 


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DISTRICT  OF  MASSACHUSETTS,  TO  WIT : 

District  Clerk's  Office. 

B«  it  remembered,  That  on  the  fifteenth  day  of  September,  A.  D.  1827,  and  in 
the  fifty-second  year  of  the  Independence  of  the  United  States  of  America,  Levi 
Hedge,  of  the  said  District,  has  deposited  in  this  office  the  title  of  a  book,  the  right 
whereof  he  claims  as  author,  in  the  words  following,  to  wit  i 

"  Elements  of  Logick;  or  a  Summary  of  the  general  Principles  and  different  Modes 
of  Reasoning.  By  Levi  Hedge,  LL.  D.  Professor  of  Natural  Religion.  Moral  Phi- 
losophy, and  Civil  Polity,  in  Harvard  University." 

In  conformity  to  the  act  of  the  Congress  of  the  United  States,  entitled,  "  An 
Act  for  the  encouragement  of  learning,  by  securing  the  copies  of  maps,  charts,  and 
books,  to  the  authors  and  proprietors  of  such  copies,  during  the  times  therein  men- 
tioned :"  and  also  to  an  act,  entitled,  "  An  Act  supplementary  to  an  act,  entitled, 
An  Act  for  the  encouragement  of  learning,  by  securing  the  copies  of  maps,  charts, 
and  books,  to  the  authors  and  proprietors  of  such  copies,  during  the  times  therein 
mentioned;  and  extending  the  benefits  thereof  to  the  arts  of  designing,  engraving 
and  etching  historical  and  other  prints." 

JOHN  W.  DAVIS, 
Clerk  of  the  District  of  Massachusetts. 


"isr^us 


Stereotyped  at  the 
Boston  Type  and  Stereotype  Foundry. 


PREFACE 

TO    THE    FIRST    EDITION. 


Most  of  the  treatises  of  Logick  in  common  use  have 
been  formed  on  the  model  of  the  ancient  systems,  and 
are  encumbered  with  many  scholastick.  subtilties  and 
unimportant  distinctions.  The  instructions,  which  they 
furnish  on  the  subject  of  ratiocination,  consist  of  very 
little  more  than  a  description  of  the  syllogism,  and  a 
few  general  principles  of  demonstrative  reasoning.  They 
contain  no  elements  nor  rules  to  assist  us  in  reasoning 
on  subjects  of  probability,  or  on  the  ordinary  events  of 
human  life.  The  manner,  in  which  these  books  are  writ- 
ten, is  ill  adapted  to  the  comprehension  of  young  minds. 
In  explaining  the  operations  of  reasoning,  many  technical 
terms  and  arbitrary  forms  are  employed,  of  which  the 
tendency  is  rather  to  embarrass  and  perplex,  than  to  in- 
struct the  learner. 

Though  much  has  been  written,  of  late  years,  on  the 
powers  and  operations  of  the  mind,  yet  there  haeve  been 
but  few  attempts  to  form  a  system  of  Logick  for  the  use 
of  those,  who  are  commencing*  the  study.  Collard  has 
improved  the  syllogism,  by  simplifying  its  principles, 
and  divesting  it  of  its  ancient  trappings  of  modes  and 
figures.  Condillac  has  proved  the  importance  of  the 
method   of  induction,    by  pointing   out   the   manner,   in 


4 


IV  PREFACE. 

which  Nature  teaches  us  to  analyze  the  objects,  which 
she  presents  to  our  observation.  In  "  An  Essay  on  the 
Elements,  Principles,  and  different  Modes  of  Reason- 
ing," by  Richard  Kirwan,  LL.  D.  all  the  subjects,  which 
properly  fall  within  the  precincts  of  Logick,  are  amply 
discussed.  But  this  work  is  too  minute  and  prolix  to  be 
used  as  a  text  book  id  seminaries  of  education.  Every 
person,  who  is  much  conversant  with  this  department  of 
knowledge,  must  have  perceived  the  want  of  a  treatise 
of  Logick,  more  elementary,  and  better  accommodated  to 
the  present  improved  state  of  the  philosophy  of  the  mind, 
than  any  of  those,  which  are  now  in  use. 

The  professed  object  of  Logick  is  to  furnish  rules  for 
the  direction  of  the  understanding  in  its  various  inqui- 
ries after  knowledge.  It  should,  therefore,  teach  the 
principles  of  every  species  of  reasoning,  which  we  have 
occasion  to  make  use  of,  both  in  the  pursuits  of  science, 
and  in  the  ordinary  transactions  of  life.  Demonstrative 
reasoning  can  be  employed  only  about  general  truths, 
and  such  relations  as  are  in  their  nature  immutable. 
It  is  of  little  use  in  regulating  our  judgments  and  con- 
clusions concerning  events,  which  are  irregular  in  their 
occurrence,  and  which  depend  on  contingent  circum- 
stances. To  reason  on  subjects  of  this  kind,  it  is  neces- 
sary to  -understand  the  nature  of  moral  evidence,  and 
the  grounds  of  probability.  It  is  by  moral  evidence 
alone,  that  we  reason  on  historical  facts,  and  the  casual 
occurrences  of  life.  It  is  also  this  evidence,  which  influ- 
ences our  conclusions  on  the  important  and  interesting 
subjects  of  government,  morals,  and  religion. 


PREFACE.  V 

Under  these  impressions,  the  writer  of  this  compend 
has  pursued  the  following  plan.  After  passing  through 
the  customary  distinctions  of  terras  and  propositions,  he 
has  given  a  brief  account  of  moral  evidence,  and  pointed 
out  the  circumstances,  which  distinguish  it  from  demon- 
strative. A  concise  view  is  then  given  of  the  different 
forms  of  reasoning,  with  the  principles,  on  which  they 
respectively  proceed. 

The  books,  which  have  been  principally  consulted  in 
forming  this  summary,  and  in  which  the  greatest  part 
of  the  following  principles  may  be  found,  are  Watts' 
Logick,  Locke's  Essay  on  the  Understanding,  Reid's 
Essays  on  the  Intellectual  Powers,  Stewart's  Elements 
of  the  Philosophy  of  the  Mind,  Beattie's  Essay  on  Truth, 
Tatham's  Chart  and  Scale  of  Truth,  Collard's  Essentials 
of  Logick,  Kirwan's  Logick,  Campbell's  Philosophy  of 
Rhetorick,  Gambier's  Introduction  to  Moral  Evidence, 
Belshara's  Compendium  of  Logick,  and  Scott's  Elements 
of  Intellectual  Philosophy. 

Where  passages  have  been  borrowed  entire,  credit  is 
given  in  the  usual  way.      At  the    close    of  the  several 
chapters  may  be  found  the  names  of  those  authors,  from 
whom  particular  assistance  has  been  derived. 
1* 


PREFACE 


TO    THE    THIRD    EDITION. 


The  present  edition  of  the  Elements  of 
Logick  is  printed  in  a  smaller  type  than  either 
of  the  preceding,  in  order  that  the  copies 
may  be  afforded  at  a  reduced  price.  The 
author  has  carefully  revised  the  work,  and 
has  enlarged  it  by  the  addition  of  a  few  pages, 
containing  some  general  principles  and  rules 
respecting  controversy,  and  also  a  system  of 
rules  for  the  interpretation  of  written  docu- 
ments. These  have  been  collected  with  care 
from  authors  of  high  reputation,  and,  it  is 
hoped,  will  not  be  thought  an  unsuitable 
appendage  to  a  system  of  logick.  In  a  few 
places,  slight  alterations  have  been  made  in 
the  language  and  in  the  arrangement  ;  and 
some  notes  have  been  inserted  at  the  end  of 
the  book,  which  were  not  in  the  preceding 
editions. 

Harvard  College,  Nov.  1821. 


CONTENTS. 


PART  FIRST. 

A     DESCRIPTION     OF     THE      LEADING     AFFECTIONS     AND 
OPERATIONS     OF     THE     MIND. 

Pago 

Introduction.        13 

CHAP.   I. 
Perception  and  Consciousness .     15 

CHAP.    II. 
Attention 19 

CHAP.    III. 
Comparing 21 

CHAP.    IV. 
Abstraction 23 

CHAP.   V. 
Association 25 

CHAP.   VI. 
Analysis 28 


PART   SECOND. 

OF    TERMS    AND    PROPOSITIONS. 

CHAP.    I. 
Logical  Distinctions  of  Terms e     .  31 


X  CONTENTS. 

CHAP.   II. 
Definition  and  Division 39 

CHAP.    III. 
General  Description  of  Propositions 43 

CHAP.    IV. 

Simple,  Complex,  and  Modal  Propositions.      ...     47 

CHAP.   V. 
Quality  and  Quantity  of  Propositions 60 

CHAP.    VI. 

Opposition  and  Conversion  of  Propositions.      ...     55 

CHAP.   VII. 
Compound  Propositions 59 


PART  THIRD. 

OF   JUDGMENT   AND    REASONING. 

CHAP.   I. 
Intuitive  Evidence 65 

CHAP.   II. 

Difference  between  Moral  and  Demonstrative 

Reasoning 70 

CHAP.   III. 
Induction 76 

CHAP.    IV. 
Analogy 83 

CHAP.   V. 
ReasoDing  on  Facts. 88 


CONTENTS.  XI 

CHAP.    VI. 
Calculation  of  Chances 101 

CHAP.   VII. 

General  Description  of  Demonstrative  Reasoning.         108 

CHAP.   VIII. 
Distinctions  of  Reasoning.       .     .     .    • 113 

CHAP.   IX. 

General  Description  of  Syllogistick  Reasoning.        .     116 

CHAP.  X. 
Regular  Syllogisms 120 

CHAP.   XI. 
Enthymemes 130 

CHAP.  XII. 
Conditional  and  Disjunctive  Syllogisms.     ....     134 

CHAP.   XIII. 
Compound  Syllogisms 137 

CHAP.   XIV. 
Sophisms 144 

CHAP.   XV. 
Disposition  or  Method 149 

CHAP.   XVI. 
Rules  of  Controversy.         157 

CHAP.  XVII. 
Rules  of  Interpretation 162 

Concluding  Remarks ...     168 

Notes  and  Illustrations*    ....••••     171 


^5 

fOFIVF 


ELEMENTS   OF   LOGICK. 


PART   FIRST. 

A  DESCRIPTION  OF  THE   LEADING  AFFECTIONS  AND  OPERA- 
TIONS OF  THE  MIND. 


INTRODUCTION. 

1.  The  purpose  of  Logick  is  to  direct  the 
intellectual  powers  in  the  investigation  of  truth, 
and  in  the  communication  of  it  to  others.  Its 
foundation  is  laid  in  the  philosophy  of  the  hu- 
man mind,  inasmuch  as  it  explains  many  of 
its  powers  and  operations,  and  traces  the  pro- 
gress of  knowledge,  from  the  first  and  most 
simple  perceptions  of  outward  objects,  to  those 
remoter  truths  and  discoveries,  which  result 
from  the  operations  of  reasoning. 

2.  Logick  instructs  us  in  the  right  use  of 
terms,  and  distinguishes  their  various  kinds. 
It  teaches  the  nature  and  varieties  of  propo- 
sitions ;    explains    their   properties,    modifica- 

2 


14  INTRODUCTION. 

fions,  and  essential  parts.  It  analyzes  the 
structure  of  arguments,  and  shows  how  their 
truth  may  be  discovered,  or  their  fallacy  de- 
tected. Lastly,  it  describes  those  methods  of 
classification  and  arrangement,  which  will  best 
enable  us  to  retain  and  apply  the  knowledge, 
which  we  have  acquired. 

3.  Though  the  understanding  would  be  in- 
capable of  any  high  degree  of  improvement, 
without  the  aid  of  rules  and  principles,  yet 
these  are  insufficient  without  practice  and  ex- 
perience. The  powers  of  the  mind,  like  those 
of  the  body,  must  be  strengthened  by  use. 
The  art  of  reasoning  skilfully  can  be  acquired 
only  by  a  long  and  careful  exercise  of  the 
reasoning  faculty,  on  different  subjects  and  in 
various  ways.  The  rules  of  logick  afford 
assistance  to  this  faculty,  not  less  important 
than  that,  which  our  animal  strength  derives 
from  the  aid  of  mechanical  powers  and  en- 
gines. They  guide  its  operations,  and  supply 
it  with  suitable  instruments  for  overcoming  the 
difficulties,  by  which  it  would  be  impeded  in 
its  search  after  truth. 

4.  In  the  following  compend,  the  subjects 
of  logick  are  distributed  into  three  parts.     The 


PERCEPTION  AND  CONSCIOUSNESS.      15 

first  contains  ;i  brief  description  of  the  lend- 
ing powers  and  operations  of  the  mind  :  The 
second,  of  the  several  kinds  of  terms  and  prop- 
ositions. The  third  comprises  an  explanation 
of  moral  and  demonstrative  evidence;  of  the 
different  modes  of  reasoning  ;  of  sophisms  ; 
and  of  method,  or  disposition. 


CHAPTER    FIRST. 

PERCEPTION    AND    CONSCIOUSNESS. 

5.  Perception  is  the  first  state  or  affection 
of  the  human  mind.  By  this  we  gain  all  our 
knowledge  of  the  powers  and  qualities  of  the 
material  objects  about  us.  The  instruments 
of  perception  are  the  five  corporeal  senses, 
seeing,  feeling,  hearing,  tasting,  and  smelling. 
All  the  intercourse,  which  the  mind  has  with 
the  material  world,  is  carried  on  by  these 
organs.  Of  the  manner,  in  which  this  in- 
tercourse proceeds,  we  have  no  knowledge. 
From  experience  we  learn,  that  a  sensible 
alteration  takes  place  in  the  mind,  whenever 
any  outward  object  is  so  situated,  as  to  affect 
either  of  the  senses.  The  change,  produced 
in  the  mind  by  the  impression  of  the  object  on 
the  organ  of  sense,  is  denominated  sensation. 


16     PERCEPTION  AND  CONSCIOUSNESS. 

The  word  perception  denotes  the  knowledge, 
that  we  gain  by  sensation,  of  some  quality  in  the 
object  ;*  which  knowledge  may  be  retained  by 
the  mind  after  the  object  is  removed,  and  it 
is  then  usually  called  an  idea  or  notion.  The 
external  object,  or  quality  perceived,  is  de- 
nominated the  object  of  perception,  or  the 
archetype  of  the  idea. 

6.  If  either  of  the  senses  be  wholly  wanting, 
the  mind  must  be  forever  destitute  of  all  that 
class  of  ideas,  which  it  is  the  office  of  that 
sense  to  furnish.  If  either  be  possessed  but 
imperfectly,  the  ideas,  received  from  it,  are 
liable  to  be  faint  and  indistinct.  But  the  usual 
effects  of  dull  organs  may  be  in  a  great  measure 
obviated,  by  an  increased  effort  of  attention, 
while  the  objects  are  present ;  as  is  manifest 
in  the  case  of  persons,  who  have  had  their 
hearing  in  some  degree  impaired. 

It  is  from  habitual  inattention  to  our  sensa- 
tions,  more  than  from  dulness  in  the  organs 

*  "  The  sensations,  which  are  excited  in  the  mind  by  external 
a  objects,  and  the  ])erceptions  of  material  qualities,  which  follow 
"  those  sensations,  are  to  be  distinguished  from  each  other  only 
"  by  long  habits  of  patient  reflection."  Stewart,  Elem.  vol.  i.  ch.  v. 
part  2d,  sect.  1st. 


PERCEPTION  AM)  CONSCIOUSNESS.      17 

of  sense,  that  so  few  of  the  objects,  which 
strike  our  senses,  leave  any  durable  traces  in 
the  mind  ;  and  that  those  notions,  which  do 
remain,  are  so  often  obscure  and  indistinct. 
As  the  perceptions  of  sense  are  the  first  ele- 
ments of  our  knowledge,  we  should  cultivate 
the  habit  of  carefully  noticing  the  things,  which 
we  see,  feel,  and  the  like  ;  in  order  that  the 
notions,  which  we  form  of  them,  may  be  clear 
and  distinct. 

7.  Consciousness,  or  reflection,  is  that  notice, 
icJiich  the  mind  takes  of  its  own  operations, 
and  modes  of  existence*  By  this  we  are 
made  acquainted  with  the  successive  changes, 
which  take  place  in  the  state  of  our  minds. 
Consciousness  is  similar  to  perception,  though 
the  qualities  of  body,  which  are  the  objects  of 
the  latter,  bear  no  resemblance  to  the  thoughts 
and  operations  of  the  mind,  which  are  the 
objects  of  the  former.  The  mind,  at  least 
whilst  we  are  awake,  is  constantly  employed 
in  some  mode  of  thinking,  or  in  some  exertion 
of  its  powers  ;  and  all  the  operations,  passions, 
and  affections  of  the  mind,  are  necessarily 
subject   to   its    own    observation.      Thus,    by 

*  See  note  A,  at  the  end  of  the  book. 


18     PERCEPTION  AND  CONSCIOUSNESS. 

consciousness,  we  learn  what  is  expressed  by 
the  words  compare,  reason,  doubt,  assent,  joy, 
in  the  same  manner  as,  by  perception,  we  gain 
a  knowledge  of  sweet,  green,  soft,  cold. 

3.  Both  perception  and  consciousness^  consid- 
ered apart  from  any  acts  of  attention,  accom- 
panying them,  are  involuntary  states  of  mind. 
We  are  often  active  in  bringing  external  objects 
within  our  view,  and  in  varying  their  position, 
for  the  purpose  of  careful  observation  ;  so,  by 
a  voluntary  effort,  we  excite  operations,  and 
cause  changes  in  the  mind  ;  but  the  knowl- 
edge, that  we  gain  in  each  case,  of  the  subjects 
thus  presented,  is  without  any  act  of  the  will. 
We  cannot  avoid  hearing  many  sounds,  and 
seeing  the  objects,  which  are  placed  before  our 
eyes.  We  are  constrained  to  smell  odours, 
taste  our  food,  and  feel  bodies,  when  in  contact 
with  our  own.  It  is  the  same  with  respect 
to  the  operations  and  states  of  the  mind.  We 
are  unable  to  compare,  reason,  abstract;  to 
feel  pain,  pleasure,  disgust,  or  the  like,  without 
being  conscious  of  those  states. 


ATTENTION.  19 


4~ 


CHAPTER   SECOND. 

ATTENTION. 

9.  Attention  expresses  the  immediate  direc- 
tion of  the  mind  to  a  subject.  The  distinctness 
of  our  notions,  the  correctness  of  our  judg- 
ments, and  the  improvement  of  all  our  intel- 
lectual powers,  depend,  in  a  great  degree,  on 
the  habitual  exercise  of  this  act.  Its  surprising 
influence,  in  improving  the  perceptive  powers, 
is  manifest  in  persons,  who  have  been  led,  by 
their  peculiar  callings,  or  by  necessity,  to  place 
uncommon  reliance  on  a  particular  sense. 

Thus  sailors,  who  are  accustomed  to  look 
at  distant  objects,  acquire  the  power  of  seeing 
and  distinguishing  things,  which,  by  reason  of 
their  distance,  are  invisible  to  common  eyes.* 
Musicians  become  capable  of  discerning  the 
minutest  difference  in  sounds.  Cooks  and 
epicures  acquire  an  uncommon  sensibility  in 
tasting  and  smelling ;  and  blind  persons  im- 
prove the  sense  of  feeling  to  such  a  degree,  as 
to  make  it,  in  some  measure,  supply  the  want 
of  sight.  These  effects  are  produced  chiefly 
by  an  increased  and  habitual  attention,  which 

*  A  seafaring  life,  especially  when  early  commenced,  has  a  ten- 
dency to  produce  some  physical  change  in  the  organ  of  vision. 


20  ATTENTION. 

enables  those  persons  to  notice  impressions, 
which  are  so  slight  and  languid,  as  wholly  to 
escape  the  observation  of  others. 

10.  Attention  is  considered*  a  voluntary  act 
of  the  mind,  but  it  is  not  at  all  times  equally 
subject  to  our  command,  and  in  young  children 
is  wholly  involuntary.  Extraordinary  occur- 
rences, which  awaken  curiosity,  and  things, 
which  interest  us  in  a  high  degree,  by  exciting 
some  violent  passion  or  emotion,  often  draw 
the  attention  so  strongly,  that  we  are  unable 
for  a  time  to  transfer  it  to  any  other  subject. 
So  intensely  are  we  sometimes  engaged,  that 
we  lose  our  account  of  time,  and  take  no  notice 
of  the  objects,  which  strike  the  senses. 

11.  Attention  is  so  essential  to  memory,  that, 
without  some  degree  of  it,  no  thought  could 
ever  be  recalled  ;  and  the  reason  why  we  com- 
mit things  to  memory  more  easily  at  one  time, 
than  another,  is,  that  we  command  our  atten- 
tion more  perfectly.  It  is  equally  necessary 
in  every  operation  of  comparing,  judging,  and 
reasoning.  Dr.  Reid  has  remarked,  "  that,  if 
"  there  be  any  thing  that  can  be  called  genius, 

*  Stewart,  Elements  of  the  Philosophy  of  the  Mind,  vol.  i.  ch,  2 
Reid,  Essays  on  the  Active  Powers,  Essay  II.  ch.  3. 


COMPARING.  21 

"  in  matters  of  mere  judgment  and  reasoning, 
"  it  seems  to  consist  chiefly  in  being  able  to 
"  give  that  attention  to  the  subject,  which  keeps 
"it  steady  in  the  mind,  till  we  can  survey  it 
"accurately  on  all  sides.  There  is  a  talent 
"of  imagination,  which  bounds  from  earth  to 
"  heaven,  and  from  heaven  to  earth,  in  a  mo- 
"  mcnt.  This  may  be  favourable  to  wit  and 
"  imagery  ;  but  the  powers  of  judging  and  rea- 
"  soning  depend  chiefly  on  keeping  the  mind 
"to  a  clear  and  steady  view  of  the  subject."* 


CHAPTER   THIRD. 

COMPARING. 

12.  When  the  mind  contemplates  two  things 
in  reference  to  each  other,  it  performs  the 
operation  of  comparing.  Thus,  when  we  say 
iron  is  harder  than  lead,  and  lead  is  heavier 
than  iron,  we  compare  these  two  substances 
with  respect  to  the  degrees,  in  which  they 
possess  the  qualities  of  weight  and  hardness. 
From  this  operation  we  derive  all  our  notions 
of  relation  ;  as  father,  cousin,  largeness,  small- 
ness,  superiority,  subjection,  and  the  like. 

*  Essays  on  the  Active  Powers,  Essay  IT.  ch.  3. 


22  COMPARING. 

We  make  comparisons  with  the  greatest  ease, 
and  frequently  without  being  conscious  of  them. 
It  is  only  by  this  operation,  that  we  are  enabled 
to  recognise  the  objects,  which  we  have  before 
known,  or  to  give  to  any  quality  or  object  an 
appropriate  name  ;  for  the  application  of  the 
name  requires  not  only  the  sensation,  produced 
by  a  present  object,  but  the  comparison  of  that 
sensation  with  one  formerly  felt.* 

13.  This  operation  is  performed  by  children 
in  their  earliest  efforts  at  speech.  It  is  by 
successively  comparing  the  sounds,  they  utter, 
with  those,  made  by  others,  that  they  learn  to 
pronounce  the  words  of  their  native  tongue. 
That  propensity  to  imitation,  which  is  always 
conspicuous  in  the  sports  of  children,  is  hap- 
pily calculated  to  improve  this  effort  of  the 
mind.  The  same  may  be  asserted  of  many  of 
those  studies,  which  usually  occupy  the  years 
of  childhood,  and  particularly  of  the  study 
of  foreign  languages.  Translations  from  one 
language  into  another  require  a  constant  and 
careful  comparison  of  the  corresponding  words 
of  different   languages  ;    an   exercise    doubly 

*  Stewart,  Elements,  vol.  i.  ch.  3. 


ABSTRACTION.  23 

important  to  children,  as  it  serves  to  improve 
their  discerning  faculties,  and  at  the  -nine  time 
leada«them  to  ascertain  the  exact  import  of 
words.  The  correctness  of  every  process  of 
judgment  and  reasoning  depends,  immediately 
or  ultimately,  on  the  accuracy  of  our  compari- 
sons. »,/ 

\h  

CHAPTER   FOURTH. 

ABSTRACTION. 

14.  Abstraction  literally  implies  the  separa- 
ting of  one  tjaing  from  another  ;  but,  as  a 
mental  operation,  it  denotes  only  a  partial 
consideration  of  any  thing.  It  is  the  act  of 
considering  one  or  more  of  the  properties  or 
circumstances  of  an  object,  apart  from  the  rest. 
Thus  we  may  consider  the  length  of  a  bridge, 
without  regarding  its  breadth  or  construction. 
We  may  speak  of  fluidity  in  water,  hardness  in 
marble,  or  sweetness  in  sugar,  without  noticing 
the  other  properties  of  those  substances.  As 
the  quality,  thus  mentally  separated  from  those 
existing  with  it,  may  be  found  in  numerous 
subjects,  the  name  applied  to  it  becomes  a 
general   term.      So  whiteness  stands   for   the 


i>4  ABSTRACTION. 

colour  of  snow,  milk,  chalk,  paper,  and  many 
other  things. 

15.  This   power,  which  the   mind  has,  of 
separating  the  qualities  combined  in  the  ob- 
jects, which  fall  under  our  observation,  and  of 
tracing  the  same  quality  in  a  multitude  of  ob- 
jects, is  the   foundation    of  all  classification, 
and  gives  rise  to  the  general  words  of  language. 
But,  notwithstanding  the  necessity  of  abstrac- 
tion in  every  act  of  classification,  it  may  be 
performed    on    individuals,    without    referring 
them  to  any  class.     This  has  occasioned  some* 
to  suppose,  that  the  formation  of  classes  re- 
quired a  distinct  operation,  which  they  called 
generalization.      Dr.  Reid  says,    "we   cannot 
"  generalize  without  some  degree  of  abstrac- 
"  tion,  but  I  apprehend  we  may  abstract  without 
"  generalizing.     For  what  hinders  me  from  at- 
"  tending  to  the  whiteness  of  the  paper  before 
"me,  without  applying  that  colour  to  any  other 
"  object  ?      The  whiteness  of  this  individual 
"  object  is  an  abstract  conception  ;   but  not  a 
"  general  one,  while  applied  to  one  individuai 
"  only.      These  two  operations,  however,  are 

*  Reid,  Intellectual   Powers,  Essay  V.  ch.  3.     Collard,   Logick, 
part  I.  ch.  2. 


ASSOCIATION. 

"subservient  to  each  other;  for  the  more  at- 
"  tributes  we  observe  and  distinguish  in  any 

"one  individual,  the  more  agreements  \ve  shall 
"discover  between  it  and  other  individuals/' 


CHAPTER   FIFTH. 

ASSOCIATION. 

16.  By  the  association  of  ideas  is  understood 
that  connexion  among  the  thoughts,  affections, 
and  operations  of  the  mind,  by  which  one  has 
a  tendency  to  introduce  another.  That  one 
idea  is  often  suggested  to  the  mind  by  another, 
and  that  sensible  objects  revive  past  trains  of 
thought,  are  facts  familiar  to  all.  Words  re- 
call  the  objects,  to  which  they  have  been  ap- 
plied ;  and  the  objects  as  readily  suggest  their 
names.  A  long  train  of  associated  thoughts 
is  sometimes  introduced  by  a  single  circum- 
stance. The  view  of  the  spot,  where  we  passed 
the  first  years  of  life,  after  a  long  absence,  will 
recall  many  interesting  events  of  childhood. 
The  first  notes  of  a  familiar  tune,  being  sound- 
ed, will  cause  the  remaining  notes  to  pass 
through  the  mind  in  regular  order. 

17.  No  principle  of  our  nature  is  productive 
of  more   important  effects,   than   this,   which 


26  ASSOCIATION. 

establishes  a  connexion  between  our  ideas, 
feelings,  and  mental  operations.  It  is  the  source 
of  numerous  errors  and  prejudices.  It  is  the 
foundation  of  all  our  local  attachments  ;  and  of 
most  of  our  prepossessions  in  behalf  of  the  gov- 
ernment and  other  institutions  of  our  country. 
It  is  to  the  principle  of  association,  that  we  are 
to  attribute  our  predilections  for  the  modes  of 
dress,  pronunciation,  and  behaviour  of  those, 
whom  we  esteem  and  respect. 

The  principles  of  association  have  been  dif- 
ferently stated.  Their  number  is  not  settled  ; 
but  the  following  are  among  the  most  obvious  : 

18.  First,  resemblance  or  analogy  is  an  ex- 
tensive principle  of  association.  We  are  often 
reminded  of  one  person,  by  the  countenance, 
voice,  or  gestures  of  another.  One  natural 
scene  suggests  another  ;  and  one  event  or  one 
anecdote  frequently  brings  another  to  our  re- 
membrance, by  the  similarity  we  observe  be- 
tween them. 

19.  Secondly,  opposition  or  contrast  is  another 
principle  of  association,  but  of  less  extensive 
influence  than  the  preceding.  The  pains  of 
hunger  and  thirst  suggest  the  pleasures  of 
eating   and   drinking.      Cold   reminds  us  of 


ASSOCIATION.  27 

heat ;  darkness,  of  light ;  and  parsimony,  of 
prodigality.  So,  among  contending  parties, 
extravagance  on  one  side  usually  drives  the 
other  to  the  opposite  extreme. 

20.  Thirdly,  another,  and  with  the  bulk  of 
mankind  the  most  extensive,  ground  of  as- 
sociation, is  continuity  or  nearness  of  lime  and 
place.  The  recollection  of  an  event,  in  which 
we  were  interested,  brings  to  our  thoughts 
many  circumstances  connected  with  it ;  as  the 
place  we  wTere  in,  when  it  happened,  or  when 
we  were  informed  of  it ;  the  persons,  who  were 
with  us  ;  and  the  peculiar  state  of  our  feelings 
at  the  time.  The  objects  we  meet  on  a  road, 
that  we  have  formerly  travelled,  successively 
remind  us  of  the  subjects,  about  which  we  were 
employed,  when  wif  passed  them  before. 

21.  A  fourth  principle  of  association  re- 
sults from  the  relations  of  cause  and  effect, 
premises  and  consequences.  The  sight  of  a 
.  surgical  instrument,  or  an  engine  of  torture, 
excites  a  strong  sense  of  the  pain,  it  is  calcu- 
lated to  occasion  ;  and  the  sight  of  a  wound 
reminds  us  of  the  instrument,  by  which  it  was 
made.  When  we  see  a  fellow  being  in  distress, 
we  are  solicitous  to  find  out  the  cause  ;   and 


28  ANALYSIS. 

when  we  have  afflictive  tidings  to  communicate, 
we  anticipate  the  grief,  which  will  be  excited. 
22.  As  one  idea  may  be  associated  with  se- 
veral others,  each  leading  to  a  different  series, 
it  is  obvious,  that  the  same  circumstance  may 
suggest  different  trains  of  thought  to  different 
persons,  and  to  the  same  person  at  different 
times.  The  association  of  ideas  is  concerned 
in  every  act  of  memory  and  recollection.  No 
thought,  after  it  has  once  passed  from  the 
mind,  could  ever  be  recalled,  were  it  not  for 
the  tendency  of  one  idea  to  introduce  another.* 


CHAPTER   SIXTH. 

ANALYSIS. 

23.  Analysis  deserves  a  place  among  the 
operations,  by  which  the  elements  of  knowledge 
are  acquired.  Without  this,  our  perceptive 
powers  would  give  us  only  confused  and  im- 
perfect notions  of  the  objects  around  us.  To 
analyze  is  nothing  more,  than  to  distinguish 
successively  the  several  parts  of  any  compound 
subject.      Nature  dictates   this  process.      We 

*  Hume,  Essays,  vol.  ii.  sect.  3.  Stewart,  Elem.  vol.  i.  ch.  5. 
Beattie,  Dissertations,  Mor.  and  Crit.  vol.  i.  ch.  2,  sect.  i.  Scott, 
Elem.  Intel.  Phil.  ch.  v.  sect.  i. 


ANALYSIS.  29 

commence  it  at  the  earliest  period  of  improve- 
ment, and  practise  it  in  all  our  efforts  to  obtain 
information.  The  objects,  which  nature  pre- 
sents to  us,  consist  of  assemblages  of  different 

qualities,  some  more  and  others  h  ily  dis- 

tinguished.    Children  early  become  acquainted 
with  the  distinguishing  properties  of  the  thii 
daily  offered  to    their    senses,    and   in   a 
years   find   out   the   characteristic k  marks  of 
numerous  classes  of  things,  and  learn  the  use 
of  Ian sni a^e. 

24.  Things,  which  have  no  immediate  re- 
ference to  material  objects,  such  as  thoughts, 
affections,  and  mental  operations,  are  analyzed 
in  the  same  manner  as  objects  of  sense.  The 
words  abstract  and  reason  denote  processes  of 
thought,  each  of  which  may  be  readily  distin- 
guished into  separate  parts,  and  these  parts 
into  others  more  remote.  The  same  may  be 
said  of  moral  qualities,  as  justice,  prudence, 
benevolence,  and  the  like.  In  these,  as  in 
sensible  objects,  there  are  certain  parts,  which 
are  instantly  noticed,  and  others,  which  are 
discovered  by  attentive  observation.  The 
analysis  begins  in  both  cases  with  the  leading 


30  ANALYSIS. 

qualities,  and  becomes  more  perfect  as  new 
qualities  are  discovered. 

25.  We  employ  analysis  in  interpreting 
symbolical  language  and  ambiguous  proposi- 
tions. Analysis  enables  us  to  investigate  causes 
by  their  effects,  and  to  find  out  the  means 
necessary  to  attain  an  end  proposed,  by  having 
the  end  first  in  view.  It  is  by  this  instrument, 
that  the  chymist  and  botanist  retrace  the  pro- 
cesses of  nature,  and  ascertain  the  qualities  of 
mineral  and  vegetable  substances. 

Analysis  will  be  further  considered  under 
the  head  of  Inductive  Reasoning.* 

*  Condillac,  Logick,  part  i.     Watts,  Logick,  part  iv.  ch.  1.     Stew- 
art, Elem.  vol.  ii.  ch.  4. 


PART   SECOND. 

OF    TERMS    AND    PROPOSITIONS, 


CHAPTER   FIRST. 

LOGICAL     DISTINCTIONS     OF     TERMS. 

26.  Words  possess  no  natural  aptness  to 
denote  the  particular  things,  to  which  they  are 
applied,  rather  than  others,  but  acquire  this 
aptness  wholly  by  convention.  Had  the  con- 
nexion between  the  name  and  the  thing  been 
established  by  nature,  there  would  have  been 
but  one  language  in  the  world.  But  we  find 
different  words  employed  in  different  countries, 
and  with  equal  advantage,  to  signify  the  same 
thing.  Thus  white,  albus,  and  Mane,  denote 
the  same  colour.  The  principal  distinctions 
of  terms  in  logick  are  the  following  : 

27.  First,  terms  are  either  simple  or  com- 
plex. A  simple  term  is  a  single  word  ;  as  man, 
horse,  tree.      A  complex  term  consists  of  two 

*or  more  words,  representing  some  object  or  asso- 
ciation, formed  to  be  the  subject  or  predicate 
of  a  proposition  ;*  as,  human  fortitude,  a  swift 

*  See  ch.  3. 


32  TERMS. 

horse,  an  amiable  deportment.  A  word,  which 
denotes  several  individuals  of  the  same  sort,  is 
called  a  collective  term  ;  as,  army,  forest,  drove. 
28.  Secondly,  terms  arc  distinguished  into 
absolute  and  relative.  An  absolute  term  is  one, 
which  represents  an  object  or  quality,  without 
intimating  its  relation  to  any  other  thing  ;  as, 
man,  river,  mountain,  roundness,  strength.  A 
relative  term  denotes  an  object  so  far  only  as 
it  is  connected  with  some  other  object.  Thus, 
father  implies  a  man  primarily,  as  he  is  con- 
sidered the  cause  of  existence  to  another  in- 
dividual, denominated,  in  reference  to  him, 
son.  These  two  terms,  intimating  each  other, 
by  a  reciprocal  reference,  are  called  correlative. 
So  patron  and  client,  husband  and  wife,  guardian 
and  ivard,  are  correlative  terms. 

There  are  other  relative  terms,  as  who, 
which,  it,  that,  and  the  like,  which  barely 
recall  certain  other  words,  before  mentioned  ; 
hence  the  words  they  refer  to  are  denominated 
antecedents. 

29.  Thirdly,  terms  are  distinguished  into 
univocal,  equivocal,  and  synonymous.  Univocal 
terms  are  such  as  have  invariably  the  same 
signification  annexed  to  them.     Thus  individual- 


TERMS.  S3 

it ii,  genus,  electricity,  are  uni vocal  terms  : 
for  they  always  signify  the  sumo  things. 
Equivocal  words  are  such  as  are  employed  in 
different  senses.  Of  this  sort  is  the  word  head, 
which  may  signify  a  part  of  a  nail,  of  an 
animal,  or  of  a  discourse.  So  the  words  post 
and  shore  are  equivocal  ;  for  they  are  used  in 
various  senses. 

That  some  words  should  be  used  in  different 
senses  is  unavoidable,  on  account  of  the  scanti- 
ness of  language,  which  does  not  afford  a 
distinct  name  for  every  idea.  Notwithstanding 
this,  we  sometimes  find  two  or  more  words 
applied  to  the  same  thing  ;  as  wave  and  billow, 
dwelling  and  habitation.  These  are  called 
synonymous  terms. 

30.  A  fourth  distinction  of  terms  is  into 
abstract  and  concrete.  An  abstract  term  is  one, 
which  signifies  some  quality  or  attribute,  without 
referring  to  any  subject,  in  which  it  may  be 
found;  as  roundness,  hardness,  equality,  firm- 
ness. Concrete  terms  denote  both  the  attributes 
and  the  subjects,  to  which  they  belong.  Some- 
times they  express  the  subjects  directly,  and 
the  attributes  indirectly  ;  and  sometimes  the 
reverse        Thus    philosopher,    statesman,    me- 


34  TERMS. 

chanick,  are  concrete  terms,  which  directly 
denote  persons,  and  indirectly  the  attributes, 
for  which  they  are  distinguished.  But  wise, 
valiant,  swift,  hard,  are  concretes,  immediately 
signifying  certain  attributes,  and  indirectly 
intimating  the  persons  or  things,  to  which 
they  belong. 

31.  Fifthly,  terms  are  either  singular  or 
universal.  A  singular  term  is  the  proper  name 
of  some  individual  person,  place,  or  thing ;  as 
Alexander,  London,  Danube,  Etna.  Proper 
names  are  given  only  to  those  things,  which 
we  have  frequent  occasion  to  mention,  as 
individuals.  The  design  of  proper  names  is 
to  represent  these,  apart  from  the  classes,  to 
which  they  belong.  Any  term,  that  does  this 
office,  is  a  proper  name  ;  and  loses  not  its 
character  as  such  by  being  applied,  as  it  fre- 
quently is,  to  several  individuals  of  the  same 
kind,  as  Peter,  John,  William. 

32.  Universal  terms,  otherwise  denominated 
common  or  appellative,  are  names  indiscrimi- 
nately applicable  to  many  individual  beings, 
whether  natural  or  artificial,  by  reason  of 
certain  properties,  which  they  possess  in  com- 


TERM  3.  35 

mon.  Thus  man,  city,  river,  mountain,  are 
universal  terms,  because  they  agree  to  all  men, 
cities,  rivers,  and  mountains. 

33.  Universal  terms  make  the  greatest  part 
of  the  words  of  every  language.  Their  sig- 
nification is  designedly  imperfect ;  comprising 
only  the  most  common  and  obvious  properties 
of  things.  They  are  abridgments  of  language, 
happily  contrived  to  facilitate  and  expedite 
the  intercourse  of  society.  Every  production 
of  nature  and  art,  and  every  property  of  mind 
and  body,  is  an  individual.  Each  has  some 
properties  peculiar  to  itself ;  and  others,  which 
it  possesses  in  common  with  many  other  beings. 

-  By  discarding  the  peculiar  properties,  and  re- 
taining under  distinct  names  those,  which  are 
common,  we  reduce  to  a  limited  number  of 
classes  the  innumerable  objects,  which  fall 
under  our  observation.  This  distribution  of 
things  into  classes  forms  what  logicians  call 
the  genera  and  species  of  things. 

34.  Species  denotes  a  sort  or  class,  including 
only  individuals  ,  and  genus  a  class  including 
under  it  tico  or  more  species.  A  species  is 
formed  by  applying  a  name  to  that  property, 
or   collection    of  properties,    in   which    many 


36  TERMS. 

individuals  are  found  to  agree.  Thus  man  is  a 
species  ;  for  the  name  is  applicable  to  an  in- 
definite number  of  individual  beings,  on  account 
of  their  agreeing  in  the  essential  properties 
of  an  erect  figure,  and  the  faculties  of  speech 
and  reason.  So  horse,  deer,  eagle,  tree, 
are  species.  Genus  implies  the  property  or 
properties,  which  different  species  possess  in 
common.  Thus  the  property  of  walking  on 
four  feet  is  the  foundation  of  the  genus  quad- 
ruped, which  applies  to  horse,  lion,  dog, 
elephant,  and  many  other  species.  So  bird 
is  a  genus,  of  which  eagle,  lark,  swan,  and 
sparroiv,  are  species. 

35.  In  the  distribution  of  things  into  genera 
and  species,  regard  is  had  to  the  comprehension 
and  extension  of  general  terms.  By  the  com- 
prehension of  a  term  is  meant  the  aggregate  of 
all  the  known  properties  of  that  thing,  or  class 
of  things,  to  which  it  is  applied.  Thus  gold 
includes  in  its  comprehension  a  material  sub- 
stance, a  yellow  colour,  superior  weight, 
ductility,  fusibility,  and  every  other  known 
property  of  that  body.  The  extension  oj  a  term 
regards  the  number  of  individual  subjects,  to 
which  it  may  be  applied.      So  the  term  gold 


TERMS.  37 

includes  in  its  extension  every  separate  parcel 
of  that  metal.  Man  includes  in  its  extension 
every  individual  of  the  human  race. 

36.    Classes  arc  multiplied  as  the  conveni- 
ence of  language  is  found  to  require  ;  nature 
having  affixed  no  limits  to  the  number,  that 
may  be  formed.      As  the  number  of  classes 
increases,    the    names,    which    express    them, 
become  more  complicate  in  their  signification, 
and  less  extensive  in  their  application  to  indi- 
viduals.    Hence  it  is  received  as  a  maxim  in 
logick,  that,  as  the  comprehension  of  a  general 
term  is  enlarged,  its  extension  must  be  dimin- 
ished ;  and  the  contrary.     The  comprehension 
of  any  species  is  obviously  greater  than  that 
of  the  genus,  to  which  it  is  subordinate  ;  for 
the  species  includes  all  the  attributes  of  the 
genus,  and  others  in  addition.     Thus,  in  the 
following    subordinate    terms,    swallow,    bird, 
animal,  all  the  attributes  of  bird  are  found  in 
swallow,  and  all  those  of  animal,  in  bird  ;   but, 
in  each  remove,  a  part  of  the  first  collection  of 
attributes  is  discarded.     The  case  is  different 
with  respect  to  their  extension  ;  that  of  animal 
is  much  greater  than  that  of  bird,  and  that  of 
bird  greater  than  that  of  swallow. 


38  TERMS. 

37.  The  ranks,  which  lie  above  any  class, 
or  which  embrace  a  wider  extension,  are 
called,  in  reference  to  it,  superior ;  and  that, 
which  terminates  the  series,  is  called  most  ge- 
neral, or  the  highest  genus.  Descending  from 
this,  each  rank  is  called  inferior ;  and  the  low- 
est class,  which  includes  only  individuals,  is 
called  the  lowest  species.  All  the  intermediate 
ranks,  between  the  highest  genus  and  the 
lowest  species,  are  termed  subaltern  ;  each 
being  indifferently  either  a  genus  or  a  species, 
according  as  it  is  considered  in  the  ascending 
or  descending  series.  Thus  bird  is  a  genus, 
when  referred  to  eagle,  raven,  sparroiv,  but 
a  species,  when  referred  to  the  more  general 
term,  animal. 

38.  The  genus  next  above  any  species  is  call- 
ed the  proximate  genus,  and  any  genus  above 
that,  a  remote  genus  of  that  species.  Thus 
quadruped  is  the  proximate,  and  animal  a  re- 
mote genus  of  horse.  The  property,  or  collection 
of  properties,  by  which  any  species  is  distin- 
guished from  every  other  species  of  the  same 
genus,  is  the  specif  ck  difference.  So  juice 
is  the  proximate  genus  of  wine ;  but  the  cir- 
cumstance of  being  pressed  from  grapes  is  the 


DEFINITION.  39 

specifick  difference,  which  distinguishes  wine 
from  cider  and  perry,  which  are  also  juices.* 


CHAPTER   SECOND. 

DEFINITION    AND    DIVISION. 

39.  Definitions  are  usually  distinguished  into 
two  kinds  :  one  nominal,  or  of  the  name  ; 
the  other  real,  or  of  the  thing.  A  definition 
of  the  name  is  merely  a  specification  of  the 
object,  to  which  a  name  is  applied.  A  definition 
of  the  thing  is  properly  an  analysis  of  a  thing, 
or  an  enumeration  of  its  principal  attributes, 

40.  Words,  which  stand  for  indivisible  ob- 
jects, admit  only  of  nominal  definitions.  These 
are  sometimes  sufficiently  explained  by  intelli- 
gible synonymous  words  ;  thus  being  denotes 
existence  ;  identity  implies  sameness.  Those, 
which  stand  for  simple  qualities  of  body,  may 
be  defined  by  referring  to  the  subjects,  in  which 
those  qualities  reside  ;  and  those,  that  denote 
mental  states,  by  describing  the  occasions,  on 
which  they  are  produced.     Thus  yellow  is  the 

*  Locke,  Essay  on  the  Understanding,  b.  iii.  ch.  3.  Reid,  Essays, 
vol.  ii.  essay  v,  ch.  1.  Belsham,  Logick,  part  i.  sect.  4  and  5. 
Kirwan,  Logick,  part  i.  ch.  2,  6ect.  2. 


40  DEFINITION. 

colour  of  gold  or  saffron.  Surprise  is  the 
passion,  or  state  of  mind,  produced  by  the 
perception  of  some  new  or  uncommon  object. 

41 .  A  real  definition  leads  us  to  a  knowledge 
of  the  nature  of  a  thing,  by  enumerating  its 
most  essential  modes  and  properties.  Thus  a 
circle  is  a  figure,  whose  circumference  is,  in 
every  part,  equally  distant  from  the  centre. 
Injustice  is  an  intentional  violation  of  another's 
rights.  Real  definition  includes  the  nominal ; 
for  an  explanation  of  the  nature  of  any  thing 
necessarily  fixes  the  signification  of  the  name, 
by  which  it  is  called.  Natural  substances,  and 
all  compound  beings,  whether  real  or  imaginary, 
are  susceptible  of  real  definitions. 

42.  Logicians  divide  a  definition  into  two 
parts,  which  are  called  genus  and  difference. 
If  the  thing  to  be  defined  be  in  any  degree 
general,  that  is,  expressed  by  a  generick  term, 
the  definition  will  be  made  up  of  the  proxi- 
mate genus  and  the  specifick  difference.  Thus 
bird  is  an  animal,  which  has  wings,  feathers, 
and  a  hard,  glossy  bill.  Animal  is  the  proxi- ' 
mate  genus,  denoting  what  bird  has  in  com- 
mon with  horse,  deer,  elephant  ;  the  other 
terms  denote  the  specifick  difference  ;  for  they 


DEFINITION. 


point  out  the  properties,  which  distinguish 
bird  from  every  other  species  of  animate.  So 
square  is  a  figure,  which  has  four  equal  sides, 
and  four  right  angles.  Figure  is  the  proximate 
genus  ;  the  other  terms  make  the  specifick 
difference. 

43.  If  the  thing  to  he  defined  be  an  individ- 
ual, having  a  proper  name,  the  definition  will 
consist  of  the  species  and  an  enumeration  of 
so  many  properties,  as  will  distinguish  that  in- 
dividual from  all  others  of  that  species.  Thus 
Mercury  is  the  planet  nearest  the  sun.  Planet 
is  the  lowest  species  ;  nearest  the  sun  is 
the  circumstance,  which  sufficiently  marks  a 
difference  between  Mercury  and  the  other 
planets.       x 

44.  There  are  many  words  in  every  lan- 
guage, which  cannot  be  defined,  because  they 
have  no  uniform  signification  affixed  to  them. 
The,  this,  that,  which,  such,  every,  good,  had, 
desirable,  and  the  like,  are  nearly  insignificant 
sounds,  till  they  are  applied  to  particular 
things,  from  which  they  borrow  a  sort  of  local 
or  temporary  meaning  :  and  they  often  signify 
different  things,  when  applied  to  different 
subjects.      Good,  applied  to  a  soldier,  means 

4* 


42  DEFINITION. 

courage  ;  to  a  Christian,  piety  ;  to  a  physician, 
skill ;  to  a  horse,  strength ;  to  a  knife,  sharpness. 

45.  Words  of  this  description,  which  have 
no  uniform  signification  affixed  to  them,  are 
wholly  employed  in  the  definition  of  other 
terms.  The  definitive  particles  have  no  other 
use,  than  to  restrain  the  latitude  of  general 
terms.  For  example,  the  man,  this  horse,  that 
tree,  such  an  object.  Here  the  names  man, 
horse,  tree,  and  object,  which  represent  whole 
classes  of  things,  are  restrained,  by  the  words 
the,  this,  that,  and  such,  to  certain  individuals, 
with  which  we  are  supposed  to  be  already 
acquainted. 

Again,  a  wide  river,  a  severe  winter,  a  de- 
lightful prospect.  The  terms  river,  winter, 
and  prospect,  are  general ;  wide,  severe,  and 
delightful,  denote  specifick  differences.  Where- 
ever  the  latitude  of  a  general  word  is  restrained 
by  a  definitive,  or  a  quality  is  attributed  to 
a  subject,  we  may  recognise  the  two  essential 
parts  of  a  definition,  namely,  genus  and  differ- 
ence. 

46.  Division  is  the  explication  of  any  whole 
by  the  enumeration  of  its  component  parts. 
Thus  a  tree  is  divided  into  trunk,  roots,  and 


PROPOSITIONS.  43 

branches  ;  animal,  into  beast,  bird,  fish,  and 
insect.  The  term,  division,  is  applicable  to 
the  resolution  of  a  treatise  or  discourse  into 
its  several  heads  or  branches  ;  also,  to  the 
consideration  of  an  equivocal  word  in  reference 
to  its  different  significations. 

The  members  of  a  division  should  exhaust 
the  subject  divided  ;  and  they  should  be  so 
opposed,  that  one  will  not  be  contained  in 
another.  The  parts,  into  which  any  thing  is 
first  divided,  should  be  the  largest  and  most 
general.  The  resolution  of  one  of  these  parts 
into  others,  more  minute,  is  called  subdivision. 
So  a  year  is  first  divided  into  months.  Month 
is  then  subdivided  into  weeks  ;  week,  into 
days,  and  so  on.  Needless  subdivisions  should 
be  avoided,  as  they  burden  the  memory,  and 
introduce  confusion.* 


CHAPTER   THIRD. 

GENERAL    DESCRIPTION    OF    PROPOSITIONS. 

47.    A  proposition  is  a  verbal  representation 
of  some  perception,  act,  or  affection  of  the  mind. 

*  Locke,  Essay,  b.iii.     Watts,  Logick,  part  i.     Kirwan,  Lcgick, 
part  i. 


44  PROPOSITIONS. 

The  constituent  parts  of  a  proposition  are  the 
subject,  the  predicate,  and  the  copula.  The 
two  first  are  called  terms,  because  they  are 
the  extremes  of  the  proposition  ;  and  they  may 
consist  of  a  single  word  each,  or  of  a  collection 
of  words,  representing  some  person,  thing,  or 
attribute. 

48.  The  subject  of  a  proposition  is  that,  con- 
cerning which  something  is  either  asserted,  de- 
nied, commanded,  or  inquired.  The  predicate  is 
that,  which  is  asserted,  denied,  commanded,  or 
inquired,  concerning  the  subject.  The  copula  is 
that,  by  which  the  other  two  parts  are  connected. 

Body  is  divisible. 
Man  is  not  omniscient. 
Be  ye  filled. 
Is  Caesar  dead  ? 

Body,  man,  ye,  and  Ccesar,  are  the  subjects  of 
these  four  propositions  ;  divisible,  omniscient, 
filled,  and  dead,  are  the  predicates  ;  is,  is  not, 
and  be,  the  copulas.  In  the  first  example,  the 
agreement  between  the  subject  and  predicate 
is  asserted  ;  in  the  second,  it  is  denied  ;  in 
the  third,  it  is  ordered  ;  in  the  fourth,  it  is 
inquired  for. 


PROPOSITIONS. 


49.  One  part  of  a  proposition  is  often  con- 
tained in  another.  In  the  following  examples, 
the  copula  is  contained  in  the  predicate  : 


I  think. 
The  sun  ii 

These  imply, 

I  am  thinking. 
The  sun  is  rising. 

So  the  copula  sometimes  includes  the  whole, 
or  a  part  of  the  predicate  ;  as,  Troy  was  ;  that 
is,  Troy  wTas  existent.  The  copula  is  always 
some  inflection  of  the  verb  to  be,  either  express- 
ed or  understood. 

A  single  word  may  contain  a  complete  pro- 
position. Thus  scribo  implies  ego  sum  scribens, 
I  am  writing.  So  rejoice,  attend,  imply  be  thou 
rejoicing  ;  be  thou  attentive. 

50.  The  subject  of  the  proposition  usually 
stands  first,  and  the  predicate  last  ;  but  this 
order  is  sometimes  inverted,  as  in  the  following 
example  : 

In  China  are  many  ingenious  artists. 

That  is, 

Many  ingenious  artists  are  [existent]  in  China. 


46  PROPOSITIONS. 

The  words,  which  constitute  the  two  terms, 

are  sometimes  so  blended  together,  that  the 

whole,  or  a  part,  of  one  is  placed  between  parts 

of  the  other.     In  the  following  example,  the 

whole  subject  intervenes  between  parts  of  the 

predicate : 

"  But  too  often  different  is  rational  conjecture  from 
melancholy  fact."     Burke. 

In  imperative  and  interrogative  propositions, 
the  copula  is  usually  placed  first.     As, 

Be  thou  faithful. 

Is  the  controversy  settled^ 

51.  An  identical  proposition  is  one,  whose 
subject  and  predicate  are  composed  of  the  same 
word  or  ivords,  and  express  precisely  the  same 
idea.  Sometimes  the  terms  are  the  same,  and 
the  ideas  different.  Thus,  home  is  home.  This 
proposition  is  not  identical  ;  for  home,  as  sub- 
ject, means  only  a  place  of  residence  ;  but  as 
predicate,  it  denotes  that  it  is  an  agreeable 
residence.  Sometimes  the  terms  are  different, 
but  express  the  same  idea.  Thus,  three  times 
three  are  nine  ;  twelve  is  the  fifth  part  of  sixty. 
Here  the  terms  are  reciprocal,  and  may  be 
substituted  for  each  other  ;  but  the  propositions 
are  not  strictly  identical. 


PROPOSITIONS.  47 

CHAPTER   FOURTH. 

SIMPLE,    COMPLEX,    AND    MODAL    PROPOSITIONS. 

52.  A  simple  proposition  is  one,  whose  sub- 
ject and  predicate  are  composed  of  simple  terms. 

[See  No.  27.]     As, 

Time  is  precious. 
Virtue  will  be  rewarded. 

A  complex  proposition  has  one  or  both  of  its 
terms  complex.  They  are  formed  in  different 
ways.  A  proposition  is  sometimes  rendered 
complex,  by  having  for  its  subject  or  predicate 
some  other  proposition,  or  words  equivalent. 
Thus, 

That  one  man  should  be  punished  for  the  crimes  of 
another  is  unjust. 

The  words,  which  precede  is,  and  which  form 
the  subject  of  this  example,  obviously  contain 
an  entire  proposition. 

53.  Frequently  the  subject  of  a  proposition 
is  first  represented  by  the  pronoun  it,  and  after- 
wards distinctly  expressed  ;  as  in  the  following 
expression  : 

"  It  is  impossible  to  guess  at  the  term,  to  which  our 
forbearance  would  have  extended."* 

*  Burke,  Regicide  Peace. 


48  PROPOSITIONS. 

The  words,  constituting  the  real  subject, 
are  here  represented  by  the  word  it,  which 
being  discarded,  and  the  subject  stated  first, 
the  proposition  will  stand  thus  : 

To  guess  at  the  term,  to  which  our  forbearance  would 
have  extended,  is  impossible. 

54.  Another  manner  of  rendering  a  proposi- 
tion complex  is  by  introducing  the  pronoun 
ivho,  which,  or  that,  for  the  purpose  of  explain- 
ing the  subject  or  predicate.     Thus, 

Cyrus,  who  founded  the  Persian  empire,  was  the  son 
of  Cambyses. 

The  words,  introduced  by  the  relative,  form  a 
complete  proposition,  which  is  called  the  in- 
cident ;  and  the  whole  proposition,  including 
this,  is  called,  in  reference  to  it,  primary,  or 
principal.  As  the  design  of  the  incident  prop- 
osition is  purely  to  explain  the  subject  or 
predicate  of  the  primary,  it  can  be  considered 
only  as  a  part  of  the  term,  in  which  it  is 
placed. 

55.  Lastly,  any  proposition  is  complex, 
whose  subject  or  predicate  is  defined,  by  an- 
nexing to-  it  a  word  of  limitation,  or  restriction. 
As, 


PROPOSITIONS.  49 

Upright  men  are  respected. 
The  mind  is  a  simple  substance. 

The  subject  of  the  first  example  is  defined  by 
the  word  upright  ;  and  the  predicate  of  the 
second,  by  the  word  simple.  These  words  re- 
strain the  latitude  of  the  general  terms,  men  and 
substance,  to  which  they  are  joined.  They 
are  equivalent  to  incidental  propositions,  and 
may  be  readily  resolved  into  them.     Thus, 

Men,  who  are  upright,  are  respected. 
The  mind  is  a  substance,  that  is  simple. 

56.  A  modal  proposition  is  one,  whose  copula 
is  qualified  by  some  word  or  words,  representing 
the  manner  of  the  agreement  or  discrepancy 
between  the  subject  and  predicate.  The  modal- 
ity of  propositions  is  frequently  expressed  by 
the  auxiliary  verbs,  may,  can,  must,  ought,  and 
the  like,  which  imply  possibility,  necessity,  or 
contingency.     Thus, 

Men  of  influence  can  do  much  good. 
Subordination  must  be  maintained. 

The  thing  asserted,  in  each  of  these  proposi- 
tions, is  not  the  simple  and  absolute  agreement 
of  the  subject  with  the  predicate,  but  barely 
5 


50  QUALITY    AND    QUANTITY 

the  nature  of  that  agreement ;  namely,  that  it 
is  possible  or  necessary.* 


CHAPTER   FIFTH. 

QUALITY    AND    QUANTITY    OF    PROPOSITIONS. 

57.  Propositions  are  further  distinguished 
into  affirmative  and  negative  ;  which  has  been 
called  a  distinction  with  respect  to  quality.  In 
affirmative  propositions,  the  predicate  and  subject 
are  asserted  to  agree.     As, 

Clovis  was  the  founder  of  the  French  monarchy. 

In  negative  propositions,  the  predicate  is  de- 
clared to  be  incompatible  with  the  subject.  This 
is  commonly  done  by  placing  the  negative  par- 
ticle not  immediately  after  the  copula.     Thus, 

The  world  is  not  eternal. 

58.  Sometimes  the  negative  particle  is  placed 
so  far  from  the  copula,  that  it  appears  to  have 
no  immediate  connexion  with  it ;  but  rather  to 
belong  to  some  other  part  of  the  proposition  : 

Not  all  the  troops  united  were  able  to  defend  the 
fortress. 

*  Watts,  Logick,  part  ii.  ch.  2.    Kirwan,  Logick,  part  i.  ch.  2. 


OF    PROPOSITIONS.  51 

Here  the  negative  word  is  placed  before  the 
subject ;  but  still  its  influence  falls  wholly  on  the 
copula,  and  makes  the  proposition  signify  the 
opposite  of  what  it  would  without  it.  This 
will  be  made  evident  by  stating  the  proposition 
thus, 

All   the   troops   united  were   not   able   to   defend   the 
fortress. 

59.  By  the  quantity  of  a  proposition  is  meant 
its  consideration  in  respect  to  the  extent  of  its 
subject  ;  and  according  as  the  subject  is  used 
in  the  whole  or  a  part  of  its  extension,  propo- 
sitions are  denominated  universal  or  particular. 
A  universal  proposition  is  one,  whose  subject  is 
a  general  term,  used  in  the  whole  of  its  extension. 
The  signs  of  universality  are  all,  each,  every, 
no,  neither,  and  the  like.     Thus, 

All  free  agents  are  accountable. 

Every  sin  is  a  violation  of  the  Divine  law. 

These  are  universal  propositions  ;  because  each 
subject  includes  an  extensive  class,  to  each 
individual  of  which  the  predicate  is  declared 
applicable. 

60.  When  the  sign  of  universality  is  omit- 
ted, or  the  indefinite  article  is  placed  before 


52  QUALITY    AND    QUANTITY 

the  general  subject,  the  proposition  is  called 
indefinite.     Thus, 

Planets  are  continually  changing  their  places. 

A  just  sovereign  regards  the  welfare  of  his  subjects. 

These  subjects  are  taken  in  their  greatest 
extent ;  for  if  there  were  any  planet,  that  did 
not  change  its  place,  or  any  just  sovereign, 
who  neglected  the  welfare  of  his  subjects,  the 
propositions  would  not  be  true. 

61.  A  particular  proposition  is  one,  whose 
subject  is  a  general  term,  but  is  taken  only  in  a 
part  of  its  extension.  The  signs  of  particular- 
ity are  some,  many,  most,  several,  few,  and  the 
like. 

Some  animals  are  amphibious. 
Many  buildings  were  destroyed. 

The  words,  some  and  many,  restrain  the  sub- 
jects, animals  and  buildings,  and  intimate,  that 
a  part  only  of  the  individual  beings,  which  they 
include,  will  admit  the  predicates,  amphibious 
and  destroyed. 

62.  A  proposition,  whose  subject  is  the 
proper  name,  of  some  individual  person  or 
thing,  is  denominated  singular.     As, 


OF    PROPOSITIONS.  53 

Alfred  founded  the  University  of  Oxford. 
Stagira  was  the  birthplace  of  Aristotle. 

A  definitive  pronoun,  placed  before  the  sub- 
ject of  a  proposition,  renders  it  singular.     As, 

That  general  was  defeated. 

The  subject  of  a  singular  proposition,  as  it 
represents  only  an  individual,  is  necessarily 
taken  in  its  whole  extension  ;  for  which  reason 
singular  propositions  are  classed  with  universal. 
Every  proposition,  therefore,  is  either  universal 
or  particular. 

63.  Besides  this  quantity  in  the  subject, 
there  is  another  quantity  in  the  predicate  of 
a  proposition  ;  for  this,  as  well  as  the  subject, 
is  taken  either  in  the  whole,  or  only  in  a  part 
of  its  extension.  The  quantity  of  the  subject 
and  that  of  the  proposition  are  the  same  ;  for 
in  every  universal  proposition,  the  subject  is 
universal;  and  in  every  particular  proposition, 
the  subject  is  particular.  But  the  quantity  of 
the  predicate  depends  on  the  quality  of  the 
proposition.  [See  No.  57.]  In  all  affirmative 
propositions  the  predicate  is  particular  :  and  in 
all  negative  propositions  it  is  universal. 
5* 


54  QUALITY    AND    QUANTITY 

64.  The  predicate  of  an  affirmative  propo- 
sition, separately  considered,  is  commonly  a 
more  general  term  than  the  subject.  It  is 
usually  a  genus,  of  which  the  subject  is  a  spe- 
cies. But,  when  united  to  the  subject,  no 
greater  extension  is  attributed  to  it  than  is 
just  sufficient  to  enable  it  to  embrace  the 
subject.  It  is  taken  in  the  whole  of  its 
comprehension,  but  in  a  part  only  of  its  ex- 
tension.    [See  No.  35.~\     For  example, 

Every  dog  is  an  animal. 

Here  it  is  barely  asserted,  that  the  predicate, 
animal,  does  extend  so  far  as  to  include  every 
individual  of  the  subject,  dog  ;  but  it  is  neither 
asserted  nor  denied,  that  it  is  susceptible  of 
a  greater  extension.  Now,  though  the  term, 
animal,  separately  considered,  is  applicable  to 
millions  of  beings  besides  dogs,  still,  in  this 
place,  it  has  no  more  extension  than  is  express- 
ly given  it  by  the  words  of  the  proposition. 
The  predicate  of  every  affirmative  proposition 
being  in  this  way  restrained  by  its  subject, 
universality  can  never  be  attributed  to  it. 

65.  But  in  negative  propositions,  the  predi- 
cate, not  being  restrained  by  a  subject,  to  which 


OPPOSITION    AND    CONVERSION  55 

it  is  declared  inapplicable,  is  taken  in  the 
whole  of  its  extension.     Thus, 

No  animal  is  a  tree. 

This  proposition  implies,  that  the  things, 
included  under  tree,  are  so  dissimilar  to  those, 
included  under  animal,  that  no  individual  can 
be  found,  to  which  the  two  terms  will  apply. 


* 


CHAPTER   SIXTH. 

OPPOSITION    AND    CONVERSION    OF    PROPOSITIONS. 

66.  Opposition  in  propositions  implies  a  dis- 
agreement in  respect  of  quality*  Two  proposi- 
tions, which  have  the  same  subject  and  the 
same  predicate,  are  said  to  be  opposite,  when 
one  absolutely  denies,  in  whole  or  in  part, 
what  the  other  affirms.  There  are  three  ways, 
in  which  propositions  of  this  sort  may  be 
opposed.  First,  a  universal  affirmative  may 
be  opposed  to  a  particular  negative.  These 
are  called  contradictory.     As, 

Every  defensive  war  is  just. 
Some  defensive  wars  are  not  just. 

Secondly,  a  universal  affirmative  proposition 
may  oppose  a  universal  negative.  These  are 
called  contrary.     As, 


56  OPPOSITION    AND    CONVERSION. 

Every  disease  is  contagious. 
No  disease  is  contagious. 

Thirdly,  a  particular  affirmative  may  be  oppos- 
ed to  a  particular  negative.  These  are  called 
subcontrary.     As, 

Some  amusements  are  innocent. 
Some  amusements  are  not  innocent. 

Two  contradictory  propositions  can  never 
be  either  both  true,  or  both  false,  at  the  same 
time  ;  two  contraries  may  be  both  false,  but 
they  cannot  be  both  true  ;  and  two  subcontra- 
ries  may  be  both  true,  but  they  cannot  be  both 
false,  at  the  same  time. 

67.  The  conversion  of  a  proposition  is  Ike 
transposition  of  its  terms,  so  that  the  subject  shall 
take  the  place  of  the  predicate,  and  the  predicate 
the  place  of  the  subject,  with  the  preservation  of 
truth.  When  the  subject  and  predicate  simply 
change  places,  without  causing  any  alteration 
in  the  quantity  of  the  propositions,  it  is  called  a 
simple  conversion.  But  if,  in  the  new  arrange- 
ment, a  term  of  particularity  is  introduced,  to 
restrain  the  subject  of  the  derivative  propo- 
sition within  the  same  extension,  which  it  had 
as  predicate  of  the  original,  this  is  called  a 
particular  conversion  ;  by  the  schoolmen  it  was 


/ 


OF    PROPOSITIONS.  57 

denominated  convcrsio per  accidens.  Universal 
affirmative  propositions  are  usually  convertible 
only  in  the  latter  mode  ;  but  universal  negatives 
and  particular  affirmatives  are  convertible  in 
the  former. 

63.  The  converse  of  a  universal  affirmative 
proposition  must,  generally  speaking,*  be  a 
particular  affirmative.  It  is  necessary  that 
both  the  terms  be  taken  in  exactly  the  same 
extension,  in  both  arrangements  ;  and  since,  by 
the  rule  stated  in  No.  63,  the  predicate  of  the 
original  proposition  must  be  particular,  this 
same  term  must  be  particular  in  the  converse, 
where  it  is  made  the  subject,  which  will  there- 
fore render  the  proposition  particular.     Thus, 

Orig.  Prop.     All  swallows  are  birds. 
Converse.         Some  birds  are  swallows. 

69.  The  converse  of  a  universal  negative 
proposition  is  a  universal  negative.  The  sub- 
ject and  predicate,  being  of  equal  extent,  mu- 
tually exclude  each  other  ;  and  as  these  terms 

*  This  is  always  the  case,  except  in  those  propositions,  whose 
predicate  is  a  complete  definition  of  the  subject.  In  such  proposi- 
tions, the  subject  and  predicate  are  reciprocal  terms.  As,  four  times 
jive  are  twenty  ;  and  ticcnty  are  four  times  fire.  Wine  is  the  juice 
of  the  grape  ;  and  the  juice  of  the  grape  is  wine. 


58  OPPOSITION    AND    CONVERSION. 

are  both  universal  in  the  first  arrangement, 
[See  No.  65.~\  they  must  be  so  in  the  second. 
Thus, 

Orig.  Prop.     No  deer  is  an  elephant. 
Converse.         No  elephant  is  a  deer. 

70.  Particular  affirmative  propositions  are 
convertible  only  into  the  same.  In  these  the 
terms  are  both  particular  ;  [See  No.  61,  63.] 
and  they  can  never  become  otherwise  by  a 
new  arrangement.     Thus, 

Orig.  Prop.    Some  birds  lie  dormant  during  the  winter. 
Converse.        Some  beings,  that  lie  dormant  during  the 
•winter,  are  birds. 

71.  A  particular  negative  proposition  is 
inconvertible  in  any  mode.  Its  subject  is  par- 
ticular, and  by  conversion  this  subject  would  be 
made  the  predicate  of  a  negative  proposition, 
and  must  therefore  be  universal,  according  to 
No.  65  ;  a  whole  deduced  from  a  part,  which 
is  impossible.  For  example  ;  from  this  propo- 
sition, 

Some  birds  are  not  swallows. 

we  cannot  affirm  this, 

No  swallows  are  birds. 

This  would  be  to  deduce  a  whole  from  a  part ; 


COMPOUND    PROPOSITIONS.  59 

since  swallow  is  denied  of  a  part  only  of  the 
extension  of  bird,  in  the  first  proposition  ;  and 
of  the  whole  of  it,  in  the  last.* 

72.  There  is  a  third  species  of  conversion, 
in  which  a  negative  particle  is  inserted  both 
in  the  subject  and  predicate  of  the  derivative 
proposition,  unless  previously  included  in  the 
original.  This  is  denominated  conversion  by 
contraposition.     Thus, 

Orig.  Prop.  Every  bird  is  an  animal. 

Converse.       That,  which  is  not  an  animal,  is  not  a  bird. 

These  negatives  destroy  each  other,  and  the 
proposition  is  considered  as  affirmative. t 


CHAPTER   SEVENTH. 

COMPOUND     PROPOSITIONS. 

73.  A  compound  proposition  is  one,  which  has 
two  or  more  subjects,  or  predicates,  or  both  ;  and 
may  be  resolved  into  two  or  more  propositions. 

*  In  a  universal  affirmative  proposition,  the  subject  only  is 
universal,  and  the  predicate  particular  ;  in  a  universal  negative,  the 
subject  and  predicate  are  both  universal ;  in  a  particular  affirmative, 
the  subject  and  predicate  are  both  particular  ;  and  in  a  particular 
negative,  the  subject  only  is  particular,  and  the  predicate  universal. 

t  Watts,  Logick,  part  li.  ch.  2.     Kir-wan,  Logick,  part  i.  ch.  3 


60  COMPOUND    PROPOSITIONS. 

As, 

Spring,  summer,  autumn,  and  winter,  are  seasons  of 
the  year. 

Alfred  was  prudent,  valiant,  just,  and  benevolent. 

As  the  four  subjects  of  the  first  example  are 

separately  applicable  to  the  predicate,  seasons 

of  the  year,  and  the  four  predicates  of  the  last, 

separately  applicable   to  the    subject,  Alfred, 

each  may  be  resolved  into  four  propositions. 

Thus, 

Spring  is  a  season  of  the  year. 
Summer  is  a  season  of  the  year,  &c. 

74.  Every  compound  proposition  may  be 
reduced  to  as  many  single  ones  as  it  contains 
subjects,  to  which  the  whole  predicate  will 
apply,  and  predicates,  to  which  the  whole  sub- 
ject will  apply  ;  or  as  there  are  parts  in  each, 
which  are  separately  applicable  to  each  other. 

Beasts,  birds,  and  insects,  have  life,  sense,  and  motion. 

This  example  contains  three  subjects  and  three 
predicates,  and  may  be  reduced  to  nine  distinct 
propositions. 

75.  Two  or  more  words  are  sometimes  so 
coupled  together  in  the  subject  or  predicate, 
as  to  give  the  proposition  the  appearance  of 


COMPOUND    PROPOSITIONS.  61 

being  compound,  when  it  is  single.     Thus, 

Joy  and  sorrow  are  opposite  qualities. 
Ye  cannot  serve  God  and  Mammon. 

These  are  complex  propositions,  but  they  are 
not  compound  ;  for  neither  of  them  can  be 
resolved  into  two  propositions.  The  two  parts, 
which  make  up  respectively  the  subject  of  the 
one  and  the  predicate  of  the  other,  must  be 
taken  conjointly. 

76.  Compound  propositions  may  be  distin- 
guished from  those,  that  are  barely  complex, 
by  the  following  circumstances.  First,  in  a 
compound  proposition,  the  parts,  which  con- 
stitute the  subject  or  predicate,  are  independent 
of  each  other,  and  may  be  taken  separatelv. 
as  well  as  conjointly  ;  which  is  not  the  case 
in  complex  propositions.  In  the  latter,  either 
certain  words  are  joined  together,  which  re- 
present integral  parts  of  some  whole,  that  is  to 
be  the  subject  or  predicate,  as,  three  and  seven 
are  equal  to  ten  ;  or  one  part  of  the  proposition 
is  repeated,  directly  or  implicitly,  by  some 
relative  word,  as,  it,  that,  icho,  which ;  or,  lastly, 
the  real  subject  or  predicate  is  defined  by  an 
explanatory  word.  In  either  of  these  cases, 
6 


52  COMPOUND    PROPOSITIONS. 

the  words,  which  render  the  proposition  com- 
plex, must  be  regarded  as  real  parts  of  the 
term,  in  which  they  occur. 

77.  Secondly,  wherever  a  complex  proposi- 
tion involves  a  simple  one,  there  will  be  the 
distinction  of  primary  and  incidental ;  and  the 
incidental  proposition  may  be  false,  while  the 
primary  is  true.  But,  in  compound  proposi- 
tions, there  exists  no  distinction  of  primary  and 
incidental,  each  part  being  independent  of  the 
rest  ;  and  the  compound  proposition  must  be 
false,  when  any  one  of  the  propositions,  it  in- 
volves, is  false,  though  the  others  be  true. 

78.  Compound  propositions  are,  in  most 
books  of  logick,  distributed  into  various  sorts, 
denominated  copulative,  disjunctive,  conditional, 
causal,  relative,  and  discretive  ;  which  denom- 
inations are  taken  from  the  particle,  employed 
in  the  composition  of  their  subject  or  predicate 
The  examples,  already  given,  belong  to  the 
first  class. 

A  disjunctive  proposition  asserts,  that  a  sub- 
ject agrees  ivith  one  of  two  or  more  named  pred- 
icates, or  a  predicate  with  one  of  two  or  more 
subjects  enumerated  ;  but  does  not  specify  which. 


COMPOUND    PROPOSITIONS.  63 

Thus, 

Either  the  sun  or  the  moon  will  be  eclipsed,  on  Christ- 
mas day. 

The  weather  will,  at  that  time,  be  either  clear  or 
cloudy. 

19.  A  discretive  proposition  consists  of  tire 
parts,  which  are  contratsed  by  reason  of  some 
apparent  opposition  or  inconsistency ',  intimated 
by  the  particles  but,  though,  notwithstanding, 
and  the  like.     As, 

Hannibal,  though  unfortunate,  was  a  great  general. 
A  man  may  deceive  his  neighbour,  but  not  his  God. 

80.  The  other  distinctions  of  this  class  are 
incorrect.  What  are  usually  termed  condi- 
tional, causal,  and  relative  propositions,  are 
nothing  more  than  different  modes  of  connect- 
ing two  entire  propositions  together.  It  is 
essential  to  the  individuality  of  a  proposition, 
that  it  have  but  one  copula.  However  com- 
pounded or  complicated  the  subject  or  predicate 
may  be,  they  must  be  connected  by  a  single 
affirmation  or  negation.  This  rule  is  violated 
in  every  instance  of  what  are  called  condition- 
al, causal,  and  relative  propositions.  The 
following  have  been  given  as  examples  of 
these  kinds : 


64  COMPOUND    PROPOSITIONS. 

If  the  sun  be  fixed,  the  earth  must  move. 
Rehoboam   was   unhappy,    because    he    followed    evil 
counsel. 

As  is  the  Father,  so  is  the  Son. 

The  first  is  given  as  an  example  of  a  condition- 
al, the  second,  of  a  causal,  and  the  third,  of  a 
relative  proposition.  But  no  one  of  them  can, 
with  any  propriety,  be  considered  as  a  com- 
pound proposition.  Each  example  consists 
of  two  entire  propositions,  possessing  distinct 
subjects,  copulas,  and  predicates  ;  and  so  put 
together  as  to  constitute  a  complete  act  of 
ratiocination.* 

*  Collard,  Logick,  part  iii.  ch.  2.     Kirwan,  Logick,  part  i.  ch.  4. 
Watts,  Logick,  part  ii.  ch.  2. 


PART   THIRD. 


OF    JUDGMENT    AND    REASONING. 


CHAPTER  FIRST. 

INTUITIVE     EVIDENCE. 

81.  Judgment  is  an  act  of  the  mind,  uniting 
or  separating  two  objects  of  thought  according 
as  they  are  perceived  to  agree  or  disagree.  The 
relation  between  these  objects  is  sometimes 
discovered  by  barely  contemplating  them,  with- 
out reference  to  any  thing  else  ;  and  sometimes 
by  comparing  them  with  other  objects,  to  which 
they  have  a  known  relation.  The  former  is 
simple  comparison  ;  the  latter  is  an  act  of 
reasoning.  The  determination  of  the  mind  in 
both  cases  is  denominated  judgment.  Every 
act  of  judgment  is  grounded  on  some  sort  of 
evidence.  That,  which  determines  the  mind  in 
simple  comparison,  is  called  intuitive  evidence ; 
and  that,  which  is  employed  in  reasoning, 
deductive. 

6* 


66  INTUITIVE    EVIDENCE. 

The  principal  kinds  of  intuitive  evidence,  of 
sources  of  intuitive  belief,  are  the  evidence 
of  sense,  of  consciousness,  of  memory,  and  of 
axioms,  or  general  principles. 

82.  The  first  source  of  intuitive  belief  is  the 
testimony  of  the  external  senses,  hearing,  seeing, 
touching,  smelling,  and  tasting.  These  organs 
come  to  their  usual  degree  of  maturity  in  in- 
fancy, and  are  employed  with  equal  confidence 
by  all  descriptions  of  people.  Men  have,  in 
every  country,  and  in  every  period  of  the 
world,  been  governed  by  their  testimony,  even 
in  their  most  important  concerns.  We  can 
no  more  question  the  existence  of  the  bodies, 
which  we  see  and  handle,  than  we  can  our  own 
existence,  or  the  truth  of  the  most  obvious 
maxim,  that  can  be  proposed  to  our  thoughts. 
On  the  evidence  of  the  senses  is  grounded  all 
our  knowledge  of  the  nature,  powers,  and  qual- 
ities of  the  material  objects  around  us.  All 
truths  relative  to  physical  science  or  to  the 
events  of  history,  and  all  those  rules  of  prudence, 
which  relate  to  the  preservation  and  health  of 
our  bodies,  must  ultimately  be  resolved  into 
this  principle,  that  things  are  as  our  senses 
represent  them. 


INTUITIVE    EVIDENCE. 


67 


83.    Consciousness  is  another  source  of  in- 
tuitive evidence.     Its  office  is  to  inform  us  of 
the  present  existence  of  our  various  passions, 
affections,  and  mental  operations.     The  whole 
science  of  the  human  mind  is  huilt  on  this  evi- 
dence ;  and  no  branch  of  knowledge  stands  on 
a  surer  foundation  ;  for  no  evidence  is  superior 
to    this,   where    it  is  completely  ascertained. 
But  it  is  sometimes  difficult  to  define  precisely 
the  subjects  of  our  consciousness.    Those,  who 
have  not  been  accustomed  to  attend  to  their 
intellectual  operations,  are  liable  to  err  in  apply- 
ing this  evidence.     I  think,  compare,  reason, 
doubt ;    I  feel  pain,  or  pleasure  ;   I  remember 
past  events.     These  are  facts,  of  which  I  am 
conscious,  and  of  which  I  am  unable  to  ques- 
tion the  reality.     The  power  of  consciousness 
is    exercised    but    imperfectly,    till   the    mind 
advances    towards    maturity.       Some*    have 
supposed  it  to  be  wholly  dormant  during  the 
years  of  childhood.     It  is  however  exercised, 
in  a  greater  or  less  degree,  by  people  of  all 
classes  ;    and  the  subjects,  about  which  it  is 
employed,  can  be  no  other   than   the  mental 
states  of  a  being,  which  each  one  calls  himself. 

*  Scott,  Intellectual  Philosophy. 


68  INTUITIVE    EVIDENCE. 

84.    As  the  evidence  of  sense  furnishes  us 
with  the  knowledge  of  things  present  in  the 
material  world,  and  the  evidence  of  conscious- 
ness informs  us  of  whatever  is  passing  in  our 
own  minds  ;   so  the  evidence  of  memory  gives 
us  immediate  knowledge  of  things  past,  whether 
of    a    material    or    intellectual    kind.      This 
evidence  has  ever  commanded  the  belief  of 
mankind  as  effectually  as  that  of  sense.     Past 
facts  and  occurrences,  of  which  we  have  a  clear 
remembrance,  are  regarded  as  certain.     This 
is  implied  by  men  in  all  their  efforts  to  gather 
knowledge  and  improvement  from  their  past 
experience.     It  is  on  this  principle,  that  causes, 
which  involve  the  lives  and  fortunes  of  men, 
are  decided  by  the  testimony  of  witnesses,  in 
courts  of  justice.     Propositions,  formerly  prov- 
ed,  may  be  relied  on  as  present  knowledge, 
though  the  reasons,  which  first    gained    our 
assent  to  them,  be  now  forgotten,  provided  we 
remember  that  we  once  carefully  investigated 
them,  and  were  then   certain  of  their  truth. 
Such  propositions  must  often  be  introduced  or 
referred   to  in  demonstrations  ;    and,   should 
doubts  be  entertained  respecting  their  truth, 
they  must  weaken  our  confidence  in  the  con- 


INTCITIVK     KNIDr.NCF.  69 

elusions,  to  which  they  arc  subservient.  Unless 
therefore  the  evidence  of  memory  he  admitted 
as  a  ground  of  certain  knowledge,  the  founda- 
tion of  demonstrative  reasoning  would  be 
destroyed. 

86.  Another  species  of  intuitive  evidence  is 
that,  which  accompanies  mathematical  axioms 
and  all  those  abstract  truths,  which  carry  their 
own  evidence  with  them,  and  are  readily  as- 
sented to,  as  soon  as  they  are  contemplated. 
Thus,  the  ichole  is  greater  than  a  part.  Things 
equal  to  the  same  are  equal  to  one  another. 
Every  effect  must  have  a  cause.  These  prop- 
ositions force  our  assent  by  irresistible  evi- 
dence, as  soon  as  we  understand  the  terms,  by 
which  they  are  expressed,  They  cannot  be 
proved  ;  because  no  principles  more  evident 
can  be  assumed,  from  which  their  truth  cJuld 
be  deduced.  In  all  demonstrative  reasoning, 
constant  use  is  made  of  these  abstract  and 
self-evident  propositions.* 

*  Bcattie,  Essay  on  Truth,  part  i.  ch.  2.  Stewart,  Elem.  vol.  ii. 
ch.  1.  Campbell,  Phil.  Rhet.  vol.  i.  ch.  5.  Scott,  Elem.  Intel.  Phil 
ch.  8,  sect,  3, 


70  DEDUCTIVE    EVIDENCE. 


CHAPTER   SECOND. 

DIFFERENCE    BETWEEN    MORAL    AND    DEMONSTRATIVE 
REASONING. 

86.  Reasoning  is  a  process,  by  which  un- 
known truths  are  inferred  from  those,  ivhich  ar-e 
already  known  or  admitted.  The  evidence, 
employed  in  reasoning,  is  deductive,  and  is  dis- 
tinguished into  two  kinds,  which  are,  moral 
and  demonstrative.  Moral  evidence  is  that 
species  of  proof ,  which  is  employed  on  subjects, 
directly  or  indirectly  connected  with  moral  con- 
duct. It  is  not  however  confined  to  such  sub- 
jects ;  but  is  extended  to  all  those  facts  and 
events,  concerning  which  we  do  not  obtain  the 
evidence  of  sense,  intuition,  or  demonstration  ; 
and  to  all  the  general  truths,  which  are  de- 
duced from  observation  and  experience.*  De- 
monstrative evidence  is  that,  by  which  we  trace 
the  relations,  subsisting  among  things,  in  their 
nature  immutable,  like  the  subjects  of  geometry 
and  arithmetick.  On  this  distinction  of  deduc- 
tive evidence  is  founded  the  most  general  divi- 
sion of  reasoning,  which  is  into  moral  or  proba- 

*  Gambier,  Moral  Evidence,  ch.  1. 


DEDUCTIVE    EVIDENCE.  71 

ble,  and  demonstrative.   The  principal  differences 
in  these  modes  of  reasoning  arc  the  following  : 

87.  First,  they  differ  in  regard  to  their  sub- 
jects. Demonstration  is  employed  about  ab- 
stract and  independent  truths,  or  those  rela- 
tions, which  are  considered  as  necessary,  and 
whose  subjects  may  be  exactly  measured  and 
defined.  The  properties  of  number  and  quan- 
tity are  of  this  sort.  They  have  no  respect  to 
time  or  place  ;  depend  on  no  cause  ;  and  are 
subject  to  no  change.  But  the  subjects  of 
moral  reasoning  are  matters  of  fact,  which 
are  in  their  nature  contingent,  and  the  varia- 
ble connexions,  which  subsist  among  things  in 
actual  existence.  Thus,  that  mercury  may  be 
congealed  Ly  cold,  that  lead  is  fusible,  that 
Hannibal  led  an  army  over  the  Alps,  that  Lisbon 
was  once  destroyed  by  an  earthquake,  and  the 
like,  are  truths  within  the  province  of  moral 
reasoning. 

88.  Secondly.  In  a  demonstration,  it  is  not 
necessary  to  examine  more  than  one  side  of 
the  question  ;  for  if  any  proposition  be  demon- 
strated to  be  true,  whatever  can  be  offered,  as 
proof,  on  the  opposite  side,  must  be  mere  fal- 
lacy.    But  in  cases  of  moral  reasoning,  there 


> 


V 


72  DEDUCTIVE    EVIDENCE. 

are  frequently  arguments  of  weight  on  both 
sides  ;  and  therefore,  in  order  to  judge  cor- 
rectly, we  must  consider  each  side  of  the 
question,  and  give  our  assent  to  that,  on  which 
there  appears  the  greatest  weight  of  evidence. 
Thus,  having  demonstrated  the  equality  of  the 
three  angles  of  a  triangle  to  two  right  ones, 
there  is  no  need  of  inquiring  what  may  be 
urged  against  the  demonstration.  But  the 
case  is  different  in  questions  of  a  moral  kind, 
as  whether  falsehood  may  be  practised  towards 
an  assassin  ;  or  whether  an  oath,  extorted  by 
violence,  be  obligatory.  In  such  questions,  the 
mind  is  often  perplexed,  and  the  judgment 
held  in  suspense  by  the  conflict  of  opposite 
reasons. 

89.  Thirdly.  Propositions,  contrary  to  those 
established  by  moral  evidence,  are  merely 
false  ;  but  those,  which  are  contrary  to  de- 
monstrated propositions,  are  not  only  false,  but 
likewise  absurd.  Thus,  the  assertion,  that 
Carthage  was  never  taken  by  the  Romans, 
though  false,  is  not  absurd  ;  for  there  was  a 
time,  when  it  was  true.  But  the  assertion, 
that  the  opposite  angles,  formed  by  two  straight^ 


DEDUCTIVE    EVIDENCE.  73 

lines  crossing  each  other,  arc  not  equal,  is  not 
only  false,  but  also  absurd. 

90.  Fourtbly.  In  demonstration  there  are  no 
degrees  ;  the  conclusion  resulting  necessarily 
from  the  definitions  and  principles,  which  have 
been  assumed  as  the  basis  of  the  reasoning. 
But  in  moral  reasoning  there  is  often  contrariety 
of  evidence  ;  and  the  degree  of  assurance,  we 
feel  in  the  conclusion,  must  depend  on  the 
degree,  in  which  the  evidence  on  one  side 
exceeds  that  on  the  other. 

91.  Fifthly.  In  every  process  of  demonstra- 
tive reasoning,  the  proofs  are  framed  into  one 
coherent  series,  each  part  of  which  must  have 
an  intuitive  agreement  with  that,  which  goes 
before,  and  with  that,  which  follows  it.  The 
longest  geometrical  demonstration  is  but  one 
uniform  chain,  the  links  of  which,  taken  sepa- 
rately, are  not  regarded  as  so  many  argu- 
ments ;  and  consequently,  when  thus  taken, 
they  prove  nothing.  But  taken  together,  and 
in  their  proper  order,  they  form  one  argument, 
which  is  perfectly  conclusive.  In  a  process  of 
moral  reasoning,  on  the  contrary,  there  is  usu- 
ally a  combination  of  many  separate  arguments, 
in  no  degree  dependent  on  each  other.     Each 

7 


74  DEDUCTIVE    EVIDENCE. 

possesses  some  weight,  and  bestows  on  the 
conclusion  a  certain  degree  of  probability  ;  of 
all  which,  accumulated,  the  credibility  of  the 
fact  is  compounded.  Thus,  the  proof,  that  the 
Romans  once  possessed  Great  Britain,  is  made 
up  of  a  variety  of  independent  arguments  :  as, 
immemorial  tradition  ;  the  testimony  of  histo- 
rians ;  the  ruins  of  Roman  buildings,  camps, 
and  walls  ;  Roman  coins,  inscriptions,  and  the 
like.  These  are  independent  arguments  ;  but 
they  all  conspire  to  establish  the  fact. 

92.  Sixthly.  It  may  be  further  noticed,  that 
the  obstacles,  which  occur  in  the  practice  of 
these  two  modes  of  reasoning,  are  of  different 
kinds.  Those,  which  impede  our  progress  in 
demonstration,  arise  from  the  large  number  of 
intermediate  steps,  and  the  difficulty  of  finding 
suitable  media  of  proof.  In  moral  reasoning, 
the  processes  are  usually  short,  and  the  chief 
obstacles,  by  which  we  are  retarded,  arise  from 
the  want  of  exact  definitions  to  our  words  ;  the 
difficulty  of  keeping  steadily  in  view  the  vari- 
ous circumstances,  on  which  our  judgment 
should  be  formed  ;  and  from  the  prejudices 
arising  from  early  impressions  and  associa- 
tions. 


DEDUCTIVE    EVIDENCE.  75 

93.  It  should  be  remarked  here,  that  the 
epithet  probable,  as  applied  by  logicians  to  the 
evidence  of  moral  reasoning,  has  a  teennical 
meaning,  altogether  different  from  its  usual 
signification.  In  common  discourse,  it  is  ap- 
plied  to  evidence,  which  does  not  command  a 
full  assent  ;  but  in  logical  discussions,  it  has  a 
more  comprehensive  meaning,  not  only  includ- 
ing every  subordinate  degree  of  moral  evidence, 
but  also  the  highest.  In  this  latter  sense,  it  is 
not  to  be  considered  as  implying  any  deficiency 
of  proof,  but  as  contradistinguishing  one  species 
of  proof  from  another  ; — not  as  opposed  to  what 
is  certain,  but  to  what  may  be  demonstrated 
after  the  manner  of  mathematicians  ; — not  as 
denoting  the  degree  of  evidence,  but  its  nature. 
It  is  the  more  important  to  keep  in  mind  this 
distinction  between  the  popular  and  technical 
meaning  of  the  term  probable,  as  the  neglect 
or  misapprehension  of  it  has  given  origin  to 
a  distrust  of  moral  reasoning,  as  inferior  in 
evidence  to  mathematical  demonstration  ;  and 
induced  many  authors  to  seek  for  a  mode  of 
proof  altogether  unattainable  in  moral  inquiries ; 


./ 


76  INDUCTION. 

and  which,  if  it  could  be  attained,  would  not 
be  less  liable  to  the  cavils  of  scepticks.* 


CHAPTER   THIRD. 

INDUCTION. 

94.  The  first  kind  of  moral  reasoning  is  that, 
by  which  we  infer  general  truths  from  partic- 
ular facts,  that  have  fallen  under  our  observa- 
tion. This  has  been  called  the  method  of 
induction.  It  is  founded  on  the  belief,  that  the 
course  of  nature  is  governed  by  uniform  laws, 
and  that  things  will  happen  in  future,  as  we 
have  observed  them  to  happen  in  time  past. 
We  can  have  no  proof  of  a  permanent  connexion 
between  any  events,  or  between  any  two  qual- 
ities either  of  body  or  mind.  The  only  reason 
for  supposing  such  a  connexion  in  any  instance 
is,  that  we  have  invariably  found  certain  things 
to  have  been  conjoined  in  fact ;  and  this  expe- 
rience, in  many  cases,  produces  a  conviction 
equal  to  that  of  demonstration. 

95.  When   a  property  has  been   found   in 

*  Reid,  Intellectual  Powers,  essay  vii.  eh.  3.  Campbell,  Phil. 
Rhet.  b.  i.  ch.  5.  sect.  2.  Gambier,  Mor.  Evid.  ch.  1.  Stewart, 
Elem.  Phil,  of  Mind,  vol.  i.  Introd.  part  ii.  sect.  2.   vol.  ii.  ch.  2.  sect.  4. 


INDUCTION.  77 

many  subjects  of  a  similar  kind,  and  no  con- 
tradictory instance  has  been  discovered,  though 
diligently  sought,  we  have  an  irresistible  per- 
suasion, that  the  same  property  belongs  to  all 
the   individuals  of  that  class.      Thus,   having 
applied  a  magnet  to  several  masses  of  iron,  and 
found   uniformly   a  strong  attraction   to   take 
place,  we  feel  no  doubt,  that  it  belongs  to  the 
nature    of  iron   to   be   thus   affected    by   that 
substance  ;  and,  though  our  experience  reaches 
only  to  a  small  part  of  the  masses  of  iron  in 
existence,  we  assert  with  confidence,  that  all 
iron   is  susceptible   of  magnetical   attraction. 
So,  having  often  noticed,  that,  by  the  applica- 
tion of  heat  to  a  certain  degree,  water  is  made 
to  boil,   and  that,  in  the  absence  of  heat  to 
a  certain  degree,  it  becomes  congealed  ;  and 
having  ascertained  these  changes  to  be  uniform, 
so  far  as  they  have  been  observed  by  ourselves 
and   others,   we   readily  ascribe   them  to  the 
nature  of  water,  and  conclude,  that  in  every 
country  water  will  boil  or  freeze,  on  being  ex- 
posed to  those  opposite  degrees  of  temperature. 
96.  In  this  way,  by  observations  and  experi- 
ments on  individuals  of  a  similar  kind,  noticing 
with  exactness  their  agreement,  or  the  circum- 
7* 


78  INDUCTION. 

stances,  in  which  they  differ,  we  obtain  general 
truths  relating  to  the  properties  and  laws  of 
material  objects.     By  the  same  inductive  pro- 
cess we  investigate  the  laws,  which  govern  the 
phenomena  of  mind.     Thus,  from  experience, 
it  has  been  ascertained,  that,  when  two  ideas 
have    been    often    presented   to  the  mind    in 
immediate  succession,  they  acquire  a  tendency 
mutually  to  suggest  each  other  ;  so  that,  when 
either  of  them  occurs  to  our  thoughts,  the  other 
readily  follows  it.      We  learn   also  from  ex- 
perience, that  the  durability  of  past  impressions 
on  the  mind  depends  greatly  on  the  attention, 
with  which  they  were  at  first  received.     From 
the  uniformity  of  these  facts  we  are   taught, 
that  contiguity  in  time  or  place  is  a  principle  of 
association  ;   and  that  attention  is  necessary  to 
memory. 

97.  As  we  deduce  the  common  properties  of 
a  single  class  of  beings  from  observations  on 
individuals  of  that  class,  so,  by  comparing 
individuals  of  different  classes,  we  discover 
important  resemblances  between  one  species 
and  another,  and  are  enabled  to  obtain  more 
extensive  conclusions.  Thus,  having  seen  the 
milk  of  several  animals  of  different  species,  and 


INDUCTION.  79 

found  it  uniformly  to  be  white,  we  conclude, 
that  the  milk  of  all  animals  is  so.  In  like  man- 
ner, having  witnessed  the  effect  of  fire  on 
several  pieces  of  gold,  iron,  lead,  and  so  forth, 
we  affirm,  that  all  metals  are  fusible.  In  this 
way,  beginning  with  individuals,  we  ascend  to 
species  ;  and  thence  proceed  from  less  general 
to  more  general  conclusions,  till  we  arrive  at 
those  abstract  propositions,  which  are  called 
axioms  or  general  truths. 

98.  This  method  of  induction  is  recommend- 
ed by  Lord  Bacon,  as  the  first  and  most  im- 
portant instrument  of  reason,  in  its  search  after 
truth.  We  employ  it  not  only  in  the  investi- 
gation of  general  truths,  relating  to  things  in 
actual  existence  ;  but  in  gaining  those  practi- 
cal rules  and  maxims,  by  which  the  common 
business  of  life  is  carried  on. 

99.  The  use  of  induction,  in  learning  the 
signification  of  words,  is  thus  happily  explained 
by  Mr.  Stewart  :  "  A  familiar  illustration  of 
"  this  process  presents  itself  in  the  expedient, 
"which  a  reader  naturally  employs  for  deci- 
"  phering  the  meaning  of  an  unknown  word,  in 
"  a  foreign  language,  when  he  happens  not  to 
"have  a  dictionary  at  hand.     The  first  sen- 


80  INDUCTION. 

"  fence,  where  the  word  occurs,  affords,  it  is 
"  probable,  sufficient  foundation  for  a  vague 
"  conjecture  concerning  the  notion,  annexed 
"  to  it  by  the  author  ;  some  idea  or  other  being 
"  necessarily  substituted  in  its  place,  in  order 
"  to  make  the  passage  at  all  intelligible.  The 
"  next  sentence,  where  it  is  involved,  renders 
"  this  conjecture  a  little  more  definite  ;  a  third 
"  sentence  contracts  the  field  of  doubt  within 
"  still  narrower  limits  ;  till  at  length  a  more 
"  extensive  induction  fixes  completely  the  sig- 
"  nification  we  are  in  quest  of.  There  cannot 
"be  a  doubt,  I  apprehend,  that  it  is  in  some 
"such  way  as  this,  that  children  slowly  and 
"  imperceptibly  enter  into  the  abstract  and  com- 
"  plex  notions,  annexed  to  numberless  words  in 
"  their  mother  tongue,  of  which  we  should  find 
"  it  difficult,  or  impossible,  to  convey  the  sense 
"  by  formal  definitions."* 

100.  In  another  place,  Mr.  Stewart  has 
described  the  manner  of  using  induction,  in 
tracing  an  event  to  its  physical  cause  :  "  As 
"  we  can,  in  no  instance,  perceive  the  link,  by 
"  which  two  successive  events  are  connected,  so 

*  Philosophical  Essays,  essay  v.  ch.  1. 


INDUCTION.  81 

uas  to  deduce,  by  reasoning  a  priori,  the  one 
"  from  the  other,  as  a  consequence  or  effect, 
"it  follows  that,  when  we  see  an  event  take 
"  place,  which  has  been  preceded  by  a  com- 
"  bination  of  different  circumstances,  it  is  im- 
"  possible    for    human    sagacity    to    ascertain, 
"  whether  the  effect  is  connected  with  all  the 
"  circumstances,  or  only  with  a  part  of  them  ; 
"  and,  on  the  latter  supposition,  which  of  the 
"  circumstances  is  essential  to  the  result,  and 
k-  which  are  merely  accidental  accessories  or 
1  concomitants.    The  only  way,  in  such  a  case, 
"of  coming  at  the  truth,  is  to  repeat  over  the 
''experiment  again  and  again,  leaving  out  all 
« the  different  circumstances  successively,  and 
"  observing  with  what  particular  combinations    ^ 
"  of  them  the  effect  is  conjoined. 

"When,  by  thus  comparing  a  number  of 
"  cases,  agreeing  in  some  circumstances,  but 
"  differing  in  others,  and  all  attended  with  the 
"same  result,  a  philosopher  connects,  as  a 
"general  law  of  nature,  the  event  with  its 
"physical  cause,  he  is  said  to  proceed  according 
"  to  the  method  of  induction."* 

•  Elements  of  the  Philosophy  of  the  Mind,  vol.  ii.  eh.  4.  sect.  1. 


82  INDUCTION. 

101.  Inductive  conclusions  will  amount  to 
moral  certainty,  whenever  our  experience  has 
been  uniform,  and  the  number  of  cases  examin- 
ed sufficiently  numerous.  But  this  reasoning 
is  liable  to  be  fallacious  through  impatience 
in  the  investigation,  by  which  judgments  are 
hastily  formed,  without  a  sufficient  accumu- 
lation of  facts.  The  number  of  instances, 
required  to  justify  a  general  conclusion,  must 
be  increased  in  proportion  as  the  facts,  from 
which  we  reason,  are  more  irregular  in  their 
appearance.  In  judging  concerning  the  prop- 
erties of  inanimate  matter,  a  general  inference 
may  sometimes  be  drawn  from  a  small  number 
of  particular  cases.  If,  for  example,  aqua 
fortis  has  been  known  to  dissolve  silver  in  one 
instance,  the  presumption  is  very  strong,  that  it 
will  do  so  in  all.  But  the  success,  which  may 
happen  to  attend  a  medicine  in  a  single  instance, 
furnishes  but  a  slight  presumption  with  regard 
to  its  general  operation  on  the  human  body. 

102.  When  our  experience  has  not  been 
uniform,  the  conclusions  we  make  will  fall 
short  of  moral  certainty.  An  equal  number  of 
favourable  and  unfavourable  instances  leaves 
the  mind  in  a  state  of  suspense,  without  exciting 


ANALOGY. 


83 


the  smallest  expectation  on  either  side.  As 
the  ratio,  which  the  instances  on  the  two  sides 
bear  to  each  other,  may  vary  indefinitely,  so 
must  the  judgments,  founded  on  them,  vary  in 
a  like  degree  from  the  neighbourhood  of  cer- 
tainty, down  to  that  of  entire  improbability.* 


CHAPTER   FOURTH. 

ANALOGY. 

103.  Analogy  is  the  foundation  of  another 
species  of  moral  reasoning,  similar  in  most 
respects  to  analytical  induction.  They  both 
proceed  on  the  same  general  principle,  that 
nature  is  consistent  and  uniform  in  her  opera- 
tions ;  so  that  from  similar  circumstances  similar 
effects  may  be  expected  ;  and  in  proportion  as 
the  resemblance  between  two  cases  diminishes, 
the  less  confidence  must  be  placed  in  the  con- 
clusions, made  from  the  one  to  the  other.  The 
word  analogy  is  used  with  much  vagueness. 
Sometimes  it  denotes  only  a  slight  and  distant 

*  Bacon,  Novum  Organum,  lib.  i.  Campbell,  Phil.  Rhet.  vol.  i 
cli.  5.  sect  2.  Beattic,  Essay  on  Truth,  part  i.  ch.  2.  sect.  G. 
Tatham,  Chart  and  Scale  of  Truth,  vol.  i.  ch.  4.  sect.  1.  Stewart, 
Elem.  vol.  ii.  ch.  4.  Gambier,  Mor.  Evidence,  ch.  2.  Scott,  Intel- 
Phil.  Appendix,  ch.  2. 


84  ANALOGY. 

resemblance  ;  as  that,  which  is  found  between 
different  species  of  the  same  genus.  Some- 
times it  implies  a  correspondence  of  different 
relations  ;  as  that,  which  exists  between  the 
fins  of  a  fish  and  the  wings  of  a  bird  ;  the 
latter  bearing  the  same  relation  to  the  air,  that 
the  former  does  to  the  water. 

104.  Inductive  and  analogical  reasoning  are 
so  similar  in  their  nature,  that  it  is  not  easy 
to  point  out  their  specifick  difference.  Every 
inductive  process  commences  with  analogy. 
The  following  circumstances  appear  to  mark 
a  distinction  between  them,  sufficient  to  justify 
their  being  treated  as  separate  articles.  First, 
induction  is  a  process  from  several  individuals  of 
a  class  to  the  whole  ~ts  conclusions  therefore 
are  always  general.  But  by  analogy  we  argue 
from  one  individual  being  to  another  of  the 
same  class  ;  and  from  one  species  to  another. 
Secondly,  the  evidence,  employed  in  analogy, 
is  wholly  indirect  and  collateral ; — the  coexist- 
ence of  two  qualities  in  one  subject  affording 
no  direct  evidence  of  their  coexistence  in  any 
other.  But  in  the  inductive  process  we  have 
direct  evidence,  that  the  property,  which  we 
apply  to  a  whole  class,  exists  in  many  individ- 


ANALOGY. 


85 


uals  of  that  class.  It  is  true,  that  in  all  induc- 
tion analogy  must  be  used  ;  for  we  can  never 
separately  examine  every  individual  of  a  whole 
class,  however  cautiously  we  may  proceed. 
So  far  as  we  extend  our  observations  or 
experiments,  the  evidence  is  direct  ;  but,  with 

;ird  to  the  remaining  subjects  of  the  class, 
the  conclusions  must  rest  wholly  on  analogy. 

105.  Analogy  is  an  unsafe  ground  of  reason- 
in"-  :  and  its  conclusions  should  seldom  be 
received,  without  some  degree  of  distrust. 
When  thing:-  resemble  each  other  in  several 
important  circumstances,  we  are  apt  to  sup- 
pose the  similitude  more  extensive  than  it 
really  is.  The  ancient  anatomists,  being  hin- 
dered by  their  superstition  from  dissecting  the 
bodies  of  men,  endeavoured  to  obtain  the 
information,  which  might  thence  have  been 
derived,  from  those  quadrupeds,  whose  internal 
structure  was  thought  to  approach  nearest  to 
that  of  the  human  body.  In  this  way  they  were 
led  into  numerous  mistakes,  which  have  been 
detected  by  the  anatomists  of  modern  times. 

106.    The  following  is  stated  by  Dr.  Reid 
as  an  example  of  analogical  reasoning  :    "  We 
"  observe  a  great  similitude  between  this  earth, 
8 


86  ANALOGY. 

•4  which  we  inhabit,  and  the  other  planets, 
"  Saturn,  Jupiter,  and  so  forth.  They  all  re- 
'--  volve  round  the  sun,  as  the  earth  does ; 
"  though  at  different  distances  and  in  different 
"  periods.  They  borrow  all  their  light  from  the 
"  sun,  as  the  earth  does.  Several  of  them  are 
*'  known  to  revolve  round  their  axes,  like  the 
"  earth,  and  by  that  means  must  have  a  like 
"  succession  of  day  and  night.  Some  of  them 
"  have  moons,  that  serve  to  give  them  light, 
"  in  the  absence  of  the  sun,  as  our  moon  does 
"  to  us.  They  are  all  in  their  motions  subject 
"  to  the  same  law  of  gravitation  as  the  earth 
"  is.  From  all  this  similitude  it  is  not  unrea- 
sonable to  think,  that  those  planets  may, 
"  like  our  earth,  be  the  habitation  of  various 
"  orders  of  living  creatures."* 

In  the  same  manner  we  may  conclude  from 
analogy,  that  the  comets  are  inhabited.  But 
this  conclusion  is  less  probable  than  the  other, 
in  the  same  proportion  as  the  comets  have 
less  resemblance  to  this  earth,  than  the  planets 
have. 

107.  There  are  many  subjects,  both  specu- 
lative and  practical,  about  which  analogy  is 

•  Essays  on  Intellectual  Powers,  essay  i.  ch.  4. 


AiNALOGY.  87 

the  only  evidence  we  can  employ.  When  a 
lawyer  is  perplexed  with  a  case,  that  falls  not 
fairly  within  the  provisions  of  any  existing 
statute,  and  for  which  his  file  affords  no  exact 
precedent,  he  is  placed  under  the  necessity  of 
tracing  remote  analogies  and  correspondences 
between  this  case  and  others  within  his  knowl- 
edge, and  of  forming  his  method  of  procedure 
by  the  equivocal  evidence,  furnished  by  such 
an  investigation.  To  reason  correctly  on  sub- 
jects of  this  nature  often  requires  more  caution 
and  discrimination,  than  are  usually  required 
in  reasoning  on  the  evidence  of  testimony  or 
experience.  "  It  is  by  the  urging  of  different 
"  analogies,  that  the  contention  of  the  bar  is 
"  carried  on  ;  and  it  is  in  the  comparison, 
"  adjustment,  and  reconciliation  of  them  with 
"one  another,  that  the  sagacity  and  wisdom 
"  of  the  court  are  seen  and  exercised."* 

103.  Analogy,  on  account  of  the  uncertainty 
which  attends  its  conclusions,  is  rarely  employ- 
ed in  scientifick  investigations.  It  serves  to 
guide  our  judgments,  where  direct  evidence 
cannot  be  obtained  ;  and  it  affords  a  degree 
of  probability,  which  is  sufficient  for  the  prac- 

*  Taley,  Polit.  Phil.  ch.  8. 


88  REASONING    ON    FACTS. 

tical  business  of  life.  The  proper  use  of  this 
instrument  is  to  defend  and  illustrate  truths, 
already  admitted  on  other  evidence.  It  assists 
to  explain  ambiguities  of  language,  and  to 
exhibit  obscure  truths  in  a  clear  and  familiar 
light.* 


CHAPTER   FIFTH. 

REASONING    ON    FACTS. 

109.  A  different  mode  of  reasoning  from  eith- 
er of  the  preceding  is  used  in  the  investigation 
of  those  important  and  interesting  truths,  which 
are  comprised  under  the  general  name  of  facts. 
These  are  for  the  most  part  so  unconnected 
and  independent,  so  transient  in  their  exist- 
ence, and  so  dissimilar  in  the  causes,  which 
produce,  and  the  circumstances,  which  attend 
them,  that  they  cannot  be  deduced  from  any 
general  principles  of  reasoning.  The  proofs, 
by  which  alone  they  can  be  established,  must  be 
derived  from  impressions,  made  on  the  senses 

*  Locke,  Essay  on  the  Understanding,  b.  iv.  ch.  16.  Campbell, 
Phil.  Rhet.  vol.  i.  b.  i.  ch.  5.  sect.  2.  Beattie,  Essay  on  Truth,  part  i. 
ch  2.  sect.  7.  Tatham,  Chart  and  Scale  of  Truth,  vol.  i.  ch.  1. 
sect.  3.  Stewart,  Elera.  Phil.  Mind,  vol.  ii.  ch.  4.  sect.  4.  Gambier, 
Moral  Evidence,  ch.  2. 


REASONING    ON    FACTS.  89 

of  some  persons,  to  whose  immediate  observa- 
tion the  facts  themselves,  or  some  appearances, 
connected  with  them,  must  have  been  present- 
ed. The  truths,  belonging  to  this  class,  form 
the  largest  and  most  valuable  part  of  our 
knowledge.  They  enter  into  the  business  of 
human  life  ;  and  deeply  involve  the  happiness 
both  of  individuals  and  of  communities. 

110.  Facts  maybe  distinguished  into  three 
classes,  in  reference  to  the  evidence,  by  which 
they  are  judged.  Some  are  admitted  on  tes- 
timony alone  ;  some  on  circumstantial  evidence 
alone  ;  and  some  on  these  two  united. 

First,  human  testimony  is  the  evidence,  on 
which  we  place  most  reliance  for  our  knowledge 
of  such  facts  as  have  not  fallen  under  our  im- 
mediate observation.  We  readily  admit  the 
reality  of  a  fact  on  the  sober  declaration  of  a 
person,  whose  veracity  we  have  no  positive 
reason  for  distrusting.  Truth  is  naturally 
agreeable  to  the  human  mind  ;  for  people 
usually  speak  as  they  think.  Xo  effort  of 
invention  is  required  to  relate  things  as  they 
are  ;  but  arts  of  deception  require  study  ;  and 
arc  seldom  practised,  but  for  criminal  purposes. 
The  moral  sense  is  rarely,  if  ever,  depraved 
8* 


90  REASONING    ON    FACTS. 

to  such  a  degree,  as  to  lose  all  preference  of 
truth  to  falsehood. 

111.  A  propensity  to  believe  what  others 
assert  has  also  its  foundation  in  the  constitution 
of  the  mind,  in  the  same  manner  as  the  ten- 
dency to  veracity.  Children  at  first  believe 
every  thing  that  is  told  them  ;  which  is  a  wise 
provision,  as  testimony  is  to  them  the  princi- 
pal means  of  obtaining  knowledge.  This  dis- 
position to  unlimited  credulity  continues,  till 
experience  begets  distrust,  and  at  length  teach- 
es the  necessity  of  restraining  our  confidence 
in  testimony  within  certain  limits. 

112.  Testimony  is  either  oral  or  written. 
Oral  testimony  is  distinguished  into  original, 
and  transmitted  or  traditional.  It  is  original 
when  it  is  derived  from  one,  who  had  sensible 
evidence  of  the  fact  asserted.  This  is  the  only 
testimony  of  this  kind,  in  which  we  can  have 
full  confidence  ;  and,  when  accompanied  by 
circumstances  of  the  most  favourable  nature, 
produces  a  firm  belief ;  even  though  it  be  the 
declaration  of  a  single  witness. 

113.  When  several  independent  original 
witnesses,  with  equal  advantages  for  knowing 
the  fact,  which  they  assert,  and  without  any 


REASONING    ON    FACTS.  91 

previous  concert,  agree  in  their  report,  they 
mutually  strengthen  each  other's  testimony. 
This  concurrence  of  several  independent  testi- 
monies is  itself  a  probability,  distinct  from 
that,  which  may  be  termed  the  sum  of  the 
probabilities,  resulting  from  the  separate  testi- 
monies of  the  witnesses  ;  a  probability,  which 
would  remain,  even  though  the  witnesses  were 
of  such  a  character  as  to  merit  no  confidence. 
That  such  a  concurrence  should  be  accidental 
is  in  the  highest  degree  improbable.  If,  there- 
lore,  concert  be  excluded,  there  remains  no 
other  cause  for  the  concurrence,  than  the  ex- 
istence of  the  fact. 

114.  That  evidence,  which  is  professedly 
given  on  a  certain  subject,  is  called  direct  tes- 
timony. But  a  declaration,  uttered  in  famil- 
iar conversation,  or  casually  made  in  the 
course  of  a  speech  or  discourse,  may  be  applied 
as  evidence  on  a  subject  in  no  way  connected 
with  that,  on  which  it  was  originally  introduc- 
ed. This  is  termed  incidental  testimony,  and 
it  is  usually  considered  of  greater  validity  than 
that,  which  is  direct ;  because,  from  the  manner 
in  which  it  was  introduced,  there  is  less  reason 


92  REASOMNG    ON    FACTS. 

to  apprehend  any  deliberate  intention  to  de- 
ceive. 

115.  When  a  witness  asserts  a  fact,  which 
he  did  not  personally  observe,  but  which  he 
received  from  the  mouth  of  some  other  person, 
his  testimony  is  called  transmitted  or  tradition- 
al. The  general  principle  with  regard  to  this 
sort  of  testimony  is,  that  the  further  it  travels 
from  its  original  source,  that  is,  from  the  im- 
mediate witness  of  the  fact,  the  weaker  it  be- 
comes. The  existence  of  a  fact,  reported  by 
several  persons  in  succession,  becomes  a  prob- 
ability, resulting  from  a  series  of  probabilities, 
successively  founded  on  each  other.  Each  per- 
son can  affirm  no  more  than  what  he  received 
from  his  immediate  informant,  and  the  channel, 
through  which  the  report  was  said  to  have 
passed  from  the  original  witness  to  him. 

116.  The  circumstances,  constituting  what  is 
called  the  credibility  of  a  witness,  are  the  follow- 
ing :  First,  sufficient  discernment,  opportunity, 
and  attention,  to  obtain  a  clear  knowledge  of 
the  fact  attested.  Secondly,  disinterestedness, 
which,  in  its  full  extent,  implies  the  absence  of 
all  expectation  of  advantage  or  detriment,  aris- 
ing from  the  testimony,  either  to  the  witness 


REASONING    OH     FACTS. 


93 


himself,    or    to    his    friends,     sect,    or    party. 
Thirdly,  integrity.     This  affords  the  strongest 
assurance  of  a  true  testimony,  inasmuch  as  it 
is  absolutely  inconsistent  with  any  intention  to 
deceive  or  prevaricate,  as  well  as  with  a  con- 
scions    ignorance   of  the    fact   attested.      To 
these  may  be  added  the  sanction  of  an  oath, 
with  a  knowledge  of  its  nature  and  of  the  high 
penalties  annexed  to  perjury.     But  testimony 
under  oath  is  principally  confined  to  juridical 
proceedings.     It  is  rarely  employed  in  settling 
historical    facts,    or    the    ordinary    events    of 
human  life.     So  far  as  a  witness  is  deficient 
in  either   of  the    above   qualifications,  so  far 
will  this  deficiency  invalidate  his  testimony. 

117.  Written  testimony  is  usually  esteemed 
stronger,  and  more  deserving  of  confidence, 
than  oral ;  for  the  record,  being  made,  for  the 
most  part,  without  a  knowledge  of  the  uses,  to 
which  it  is  afterwards  applied,  may  be  presum- 
ed to  have  been  made  without  any  undue  bias  ; 
and  the  witness  has  more  time  to  contemplate 
the  fact,  and  weigh  the  circumstances,  so  as  to 
render  his  account  accurate.  Further,  as  the 
record  of  facts  is  usually  made  soon  after  they 
occur,   this    testimony  is  secure   against   any 


94  REASONING    ON    FACTS. 

suspicions,  arising  from  the  imperfection  of 
memory,  which  often  weakens  the  force  of  oral 
testimony,  especially  on  subjects  of  a  distant 
date,  where  circumstances  are  liable  to  be 
forgotten,  and  conjectures  substituted  in  their 
stead. 

118.  Written  testimony  is  also  less  liable  to 
have  its  credibility  impaired  by  transmission 
than  oral.  For,  as  the  original  record  is  com- 
monly preserved  for  many  years,  it  may  be 
compared  with  the  successive  copies,  and  the 
slightest  disagreement  may  easily  be  detected. 
Whereas  oral  testimony  is  fugitive  in  its  na- 
ture, and  the  existence  of  the  original  witness 
must  be  determined  by  the  testimony  of  a  sec- 
ond witness,  whose  existence  must  be  admitted, 
in  like  manner,  on  the  credibility  of  a  third, 
and  so  on.  Besides,  the  care,  which  copying 
requires,  gives  a  copy  a  preference  to  transmit- 
ted oral  testimony.  Mistake,  in  the  former,  is 
much  less  likely  to  be  committed. 

119.  If  several  independent  copies  be  taken 
of  an  original  record,  and  these  agree  in  all 
material  circumstances,  their  credibility,  with 
respect  to  the  object  testified,  is  nearly  equal 
to  that  of  the  original  record.     For  it  is  highly 


REASONING    ON     FACTS.  95 

probable,  that  the  different  copies  would  sub- 
stantially agree  ;  and  scarcely  possible,  that 
the  same  error  should  be  committed  in  all.  The 
same  remark  is  applicable  to  all  the  successive 
copies,  and  the  more  numerous  they  are,  the 
more  they  strengthen  each  other. 

120.  In  all  plural  testimony,  whether  oral 
or  written,  the  several  witnesses  are  required 
to  agree  in  every  important  circumstance. 
But  in  things  of  minor  consequence,  a  certain 
degree  of  discrepancy  tends  rather  to  increase, 
than  to  diminish,  the  credibility  of  the  testi- 
mony ;  for  such  a  discrepancy  is  what  must 
naturally  be  expected  from  different  persons, 
describing  the  same  things. 

121.  General  notoriety  is  a  ground  of  belief, 
extending  both  to  specifick  facts  and  general 
truths.  It  is  a  species  of  testimony  differ- 
ent from  either  of  the  preceding  in  this,  that 
the  information  is  not  derived,  immediately  or 
remotely,  from  any  one,  who  pretends  to  have 
personally  witnessed  the  fact,  or  investigated 
the  truth  in  question.  No  person  can  examine 
every  subject  for  himself,  so  as  to  have  full 
knowledge  of  the  truth  of  every  proposition, 
which  he  finds  it  necessary  to  believe.     Many 


96  REASONING    ON    FACTS. 

things  must  be  received  on  trust.  Most  men 
can  give  no  better  reason  for  their  belief  of 
the  greater  part  of  the  facts  and  general  truths, 
which  they  receive,  than  that  they  find  them 
universally  believed  by  others. 

122.  The  weight  of  this  evidence  depends 
partly  on  the  presumption,  that,  unless  the 
assertions  were  true,  their  falsehood  would 
have  been  detected  ;  and  partly  on  experience  ; 
for,  though  we  are  in  the  constant  practice  of 
admitting  them  as  unquestionable  truths,  we 
rarely  find  ourselves  deceived. 

123.  This  species  of  evidence  should  not  be 
applied  without  discrimination.  Mathematical 
subjects  admit  of  being  certainly  known,  and 
mistakes  respecting  them  may  be  easily  cor- 
rected. In  these,  therefore,  propositions  uni- 
versally believed  may  be  relied  on  with  safety. 
The  same  may  be  observed  of  all  assertions 
concerning  the  existence  and  qualities  of  ma- 
terial things  ;  and  also  concerning  those  facts 
and  events,  which  are  subject  to  the  observa- 
tion of  many  persons.  But  the  case  is  differ- 
ent with  respect  to  those  propositions,  which, 
if  false,  could  not  be  easily  disproved  ;  such, 
for  example,  as  relate  to  events,  which  could 


REASONING    ON    FACTS.  97 

have  been  observed  only  by  a  few  persons  ;  or 
to  things,  supposed  to  have  happened  in  re- 
mote antiquity,  or  in  fabulous  ages.  G<  neral 
notoriety  or  universal  belief,  with  regard  to 
such  propositions,  is  not  a  sufficient  ground  of 
assent. 

124.  Secondly,  there  are  many  events  and 
occurrences,  which,  as  they  happen  not  within 
the  notice  of  any  one,  can  be  judged  of  only 
by  a  train  of  circumstances ;  and  this  evidence 
often  produces  a  higher  degree  of  assurance, 
than  the  testimony  of  living  witnesses.  Cir- 
cumstances can  neither  falsify  nor  withhold 
the  truth  ;  and  an  event  is  considered  as  well 
established,  when  a  number  of  these  are  of 
such  a  nature,  that  they  cannot  be  satisfactorily 
accounted  for  in  any  way,  but  by  admitting 
the  event  in  question. 

125.  Belief,  grounded  on  circumstantial  evi- 
dence, is  usually  denominated  presumption  ; 
and  presumptions  are  either  slight  or  violent, 
according  as  the  circumstances  noticed  are 
more  or  less  necessary  to  the  fact  supposed,  or 
do  more  or  less  usually  and  exclusively  attend  it. 
Thus,  the  presumption,  that  a  person  is  the 
author  of  an  essay,  barely  because  the  hand- 

9 


98  REASONING    ON    FACTS. 

writing  resembles  his,  is  only  slight  ;  for  one 
person  may  imitate  the  hand  of  another,  and 
two  persons  may  resemble  each  other  in  their 
usual  manner  of  writing.  But,  to  render  the 
presumption  violent,  the  circumstance  must  be 
such,  not  only  as  would  necessarily  have  at- 
tended the  fact,  had  it  existed,  but  such  as 
could  not  be  supposed  to  have  existed  ;  unless 
the  fact  in  contemplation  had  existed  likewise. 
Thus,  a  cottage,  discovered  on  a  desolate 
island,  affords  a  violent  presumption,  that  some 
human  being  had  been  there  before.  A  shel- 
ter of  some  kind  would  be  a  natural,  if  not  a 
necessary  consequence  of  a  person's  having 
resided  there  ;  and  there  is  no  other  way,  by 
which  the  existence  of  the  cottage  can  be 
accounted  for. 

The  fact,  on  which  a  presumption  is  ground- 
ed, must  be  clearly  proved  ;  for  a  presumption 
cannot  be  raised  on  a  mere  conjecture. 

126.  Thirdly,  the  credibility  of  attested  facts 
may  be  heightened  by  the  analogy  of  those 
facts  to  our  general  experience  in  similar  cases, 
or  to  what  reason  would  lead  us  to  expect. 
This  analogy  is  denominated  internal  evidence. 
Facts,  which  are  rendered  probable  by  inter- 


REASONING    ON    FACTS.  99 

nal  evidence,  may  have  their  probability  in- 
creased by  testimony,  though  in  different  de- 
grees. If  an  asserted  fact  agree  with  our  con- 
stant and  invariable  experience,  its  probability 
can  be  but  little  augmented  by  the  most  unex- 
ceptionable testimony.  Thus,  the  freezing  of 
water  is  so  common  in  our  climate,  that,  should 
any  person  affirm,  that  Charles  river  was  frozen 
over  in  February,  fifty  years  ago,  we  could 
have  no  hesitancy  in  believing  it.  Nor  would 
our  assurance  of  the  fact  be  increased,  by  the 
united  testimony  of  five  hundred  witnesses,  ot 
the  most  undoubted  veracity. 

127.  Where  the  internal  probability  is  less, 
more  testimony  is  required  to  produce  belief; 
as,  if  it  were  asserted,  that  there  was  thunder 
in  May,  or  frost  in  October,  in  any  particular 
year.  These  events,  happening  not  uniformly, 
though  much  oftener  than  they  fail,  receive  but 
a  slight  confirmation  from  past  experience. 

128.  Those  facts,  which  are  called  indiffer- 
ent or  cqiiicasnal,  by  reason  of  the  irregularity 
of  their  appearance,  belong  exclusively  to  the 
province  of  testimony  ;  as,  whether  a  ship  sailed 
on  Tuesday  or  on  Friday  ;  whether  a  man  made 
his  will,  or  died  intestate.     The  probability, 

I 


100  REASONING    ON    FACTS. 

that  any  asserted  fact  of  this  sort  happened  at 
any  specified  time  or  place,  will  be  just  equal 
to  the  credibility  of  the  witnesses  attesting  it. 

129.  If  the  asserted  fact  be  of  an  extraordi- 
nary nature,  and  one,  that  militates  with  our 
general  experience  in  similar  cases,  it  will  be 
assented  to  with  difficulty  ;  as,  if  it  were  as- 
serted, that  there  was  snow  in  August,  or  that 
the  same  number  drew  the  highest  prize  in  five 
successive  lotteries.  The  internal  improbabil- 
ity of  such  facts  must  be  overcome  by  an  in- 
creased weight  of  testimony. 

130.  Those  facts  or  events,  which  are  admit- 
ted with  the  greatest  difficulty  of  all,  are  such 
as  are  supernatural,  or  miraculous.  These, 
contradicting  our  invariable  experience,  and 
opposing  the  well  known  laws  of  corporeal 
nature,  are  in  themselves  in  the  highest  degree 
improbable  ;  and  require  for  their  belief  a 
testimony  so  ample,  and  attended  by  such 
circumstances,  as  would  render  its  falsehood 
no  less  miraculous  than  the  fact  attested.* 

*  (Gilbert,  Law  of  Evidence.  Kirwan,  Logick,  part  iii.  ch.  C. 
Locke,  Essay  on  the  Understanding,  b.  iv.  ch.  16.  Gambier,  Moral 
Evidence,  ch.  2. 


s- 


CALCULATION    OF    CHANCES.  101 

CHAPTER   SIXTH. 

CALCULATION    OF    CHANCES. 

131.  By  chance  is  not  meant  the  negation  of 
a  cause,  but  our  ignorance  of  it.  Every  change 
in  the  universe  must  proceed  from  some  ade- 
quate cause.  When  we  speak  of  events  as 
happening  fortuitously,  or  by  chance,  we  mean 
no  more,  than  that  the  causes,  which  produce 
them,  are  wholly  unknown  to  us.  The  bare 
possibility  of  an  event  is  often  denominated  a 
chance  ;  and  where  there  are  several  known 
causes  equally  capable  of  producing  different 
events,  it  is  manifest,  that  there  are  so  many 
chances  of  those  events  ;  and  that  no  one  of 
them  is  more  probable  than  the  rest. 

132.  The  doctrine  of  chances  is  that,  which 
teaches  the  degree  of  probability  or  improbabil- 
ity of  any  one  of  a  given  number  of  events,  con- 
sidered as  equally  possible.  Thus,  on  throwing 
a  die,  it  is  certain  that  some  one  of  its  six  faces 
will  be  turned  up  ;  but,  as  only  one  of  these  six 
faces  can  present  an  ace,  the  chance  of  throw- 
ing an  ace  is  only  one  out  of  six  chances,  or  £ ; 
and  the  chances  against  it  are  five  out  of  six, 
or  I  of  a  certainty.     Hence  the  general  rule 

9* 


102  CALCULATION    Ok     CHANCES. 

is,  that  the  probability  or  improbability  of  any 
event  is,  as  the  number  of  the  favourable  chances, 
divided  by  the  sum  of  all  the  chances,  both  fa- 
vourable and  unfavourable, 

133.    The  degree  of  probability,  that    any 
event  will  or  will  not  happen,  is  conveniently 
expressed  by  a  fraction,  whose  numerator  rep- 
resents the  number  of  chances,  which  favour 
the  existence,  or  the  nonexistence  of  the  event ; 
and  whose  denominator  is  the  sum  of  all  the 
chances,  both  favourable  and  adverse  to  the 
event.     Thus,  if  an  event  have  five  chances  to 
happen  and  three  to  fail,  the  fraction  t  will  ex- 
press the  probability  of  its  happening,  and  the 
fraction  t,  that  of  its  failure.     These  two  frac- 
tions, which  represent  all  the  chances,  both  of 
happening  and  failing,  being  added  together, 
their  sum  will  always  be  equal  to  unity  ;   since 
the  sum  of  their  numerators  will  be  just  equal 
to   their    common    denominator.     And    as    in 
every  case  it  is   certain,  that    an    event   will 
either  happen  or  fail,  it  follows,  that  certainty 
is  justly  represented  by  unity. 

134.  The  expectation  of  obtaining  a  benefit, 
which  depends  on  the  happening  of  an  uncer- 
tain event,  has  a  determinate  value  before  the 


CALCULATION    OF    CH  V-NCE3.  103 

event  takes  place.  The  value*$|C#j&r€>;}H  <  ia 
tion  is  in  all  cases  estimated  by  multiplying 
value  of  the  benefit  expected  by  the  fraction, 
which  represents  the  probability  of  obtaining  it. 
Thus,  if  60  crowns  be  promised  a  person  on 
condition  of  his  throwing  a  particular  face  on 
a  die,  his  expectation  before  trial  is  worth  10 
crowns,  since  he  has  one  chance  in  six,  or  £  of 
a  certainty  of  gaining  the  whole  sum. 

135.  Events  are  either  independent  or  de- 
pendent. Two  events  are  independent,  when 
they  have  no  connexion  with  each  other,  and  the 
happening  of  one  neither  promotes  nor  hinders 
the  happening  of  the  other.  Thus,  throwing 
an  ace  on  one  die  affects  not  the  possibility  of 
throwing  it  again  on  the  same,  or  on  another 
die.  But  the  possibility  of  a  joint  event  on  two 
dice,  though  each  is  independent  of  the  other, 
singly  considered,  is  affected  by  all  the  possibil- 
ities of  failure  in  each  of  the  conjoined  events. 
Now  there  are  thirty-six  possible  events  on 
two  dice  considered  conjointly  ;  for  each  has 
six  faces,  and  each  face  of  the  one  may  be  com- 
bined with  each  face  of  the  other.  Therefore 
the  possible  appearances  are  6  X  6  =  36.  But, 
of  these  combinations,  there  is  but  one  pro- 


104  CALCULATION    OF    CHANCES. 

ductive  of  the  appearance  of  two  aces,  or  any 
other  two  faces.  So  that  the  chance  of  throw- 
ing two  aces  either  together  on  two  dice,  or 
successively  on  one  die,  is  only  A. 

136.  Hence  the  probability  of  two  or  more 
independent  but  joint  events  is  equal  to  the 
product  of  the  chances  of  each.  Thus,  the 
probability  of  throwing  three  aces  successively 
on  one  die  is  £  X  i  X  i  =  *£?.  So  if  the  proba- 
bility, that  one  man,  A,  will  live  a  year,  be  A, 
and  the  probability  of  the  life  of  another  man, 
B,  for  one  year,  be  A,  the  probability,  that 
both  will  live  another  year,  is  but  t<t  X  ts<j  = 
rcnr.  Hence  the  concurrence  of  two  events  is 
less  probable  than  the  occurrence  of  either ; 
and  is  even  improbable,  though  each  is  prob- 
able and  completely  independent  of  the  other. 

137.  From  the  foregoing  rule  it  is  manifest, 
that  the  joint  occurrence  of  two  or  more  equi- 
casual,  independent  events  is  improbable  ;  and 
the  more  so,  the  more  numerous  they  are.  For 
the  probability  of  each  is  £  ;  therefore  the  joint 
chance  of  two  such  events  is  ^  X  1  =  I ;  and  of 
three  such  events  is  i  X  i  X  i=$.  So  the  con- 
currence of  two  independent,  improbable  facts 
is  still  more  improbable.     For,  supposing  the 


CALCULATION    OF    CHANCES.  105 

improbability  of  one  of  them  to  be  *,  and  that 
of  the  other  i,  their  joint  improbability  would 

be  a\r.  By  the  same  rule,  the  improbability 
of  the  death  of  A  within  a  year  being  Ar5  and 
that  of  the  death  of  B  within  a  year  t<t,  the  im 
'>:il>ilitv,  that  both  will  die  within  a  year, 
—  xSu.  And  the  probability  that  one 
of  the  events  will  happen  and  the  other  fail  is, 
as  the  probability  of  the  happening  of  the  one, 
multiplied  by  the  probability  of  the  failure  of 
the  other.  So,  in  the  above  case,  the  prob- 
ability, that  A  will  live  and  that  B  will  die, 
is  ft  X  rj  =  t\&.  And  the  probability,  that 
B  will  live  and  that  A  will  die,  is  t<j  X  T4o  = 

138.  A  dependent  event  is  one,  whose  exist- 
<  nee  is  rendered  more  or  less  probable  by  the 
chances  attending  the  existence  of  another  event. 
When  several  events  are  connected  in  such  a 
manner,  that  the  second  depends  on  the  first, 
the  third  on  the  second,  and  so  on,  the  prob- 
ability  of  the  first  or  independent  event  must 
be  first  ascertained  ;  that  of  the  second,  which 
depends  on  the  first,  is  then  found,  by  mul- 
tiplying its  separate  probability  into  that  of 
the  first ;  and  the  product  will  give  the  real 


106  CALCULATION    OF    CHANCES. 

probability  of  the  second  event.  In  the  same 
manner  we  proceed  to  find  the  probability  of 
a  third  or  fourth  dependent  event. 

139.  Thus,  suppose  six  white  and  six  black 
balls  to  be  placed  in  a  box,  and  through  a  hole 
in  the  box,  two  balls  to  be  successively  drawn 
out ;  and  let  it  be  required  to  determine  the 
probability,  that  both  these  will  be  white.  As 
there  are  twelve  balls  in  the  box,  and  six  of 
them  are  white,  it  is  evident,  that  the  proba- 
bility of  drawing  a  white  ball  at  the  first  trial 
will  be  tV  But  the  chance  of  doing  this  on 
the  second  trial  will  be  different ;  for,  as  one 
of  the  balls  has  been  taken  out,  there  are  but 
eleven  remaining ;  and  since,  in  order  to  the 
second  trial,  it  is  necessary  to  suppose,  that  the 
ball  removed  was  a  white  one,  the  remaining 
number  of  these  is  reduced  to  five.  The  sep- 
arate probability,  therefore,  of  drawing  a  wThite 
ball  at  the  second  trial  will  be  only  A  ;  and 
the  chance  of  drawing  it  the  first  and  second 
time  will  be  &  =  fX  t5t  =  ?¥.  The  separate 
probability  of  drawing  out  a  white  ball  at  a 
third  trial,  since  two  white  balls  have  been 
removed,  will  be  tV  ;  and  the  chance  of  draw- 
ing three  white  ones  at  three  successive  trials 
will  be  i  X  tV  X  tV  =  Mr  =  +- 


CALCULATION    OF    CHANCES.  107 

140.  Again,  W  sailed  for  Africa  in  a  fleet 
of  twelve  ships,  three  of  which  were  lost  in  a 
storm,  on  the  first  part  of  the  voyage.  Of  the 
crews  of  the  nine  ships,  that  escaped  the  storm, 
one  third  part  perished  from  the  hardships, 
they  met  on  the  voyage.  We  wish  to  ascertain 
the  probability,  that  W  has  escaped  both 
calamities.  Now,  as  the  chance  of  his  having 
survived  the  hardships  of  the  voyage  depends 
on  the  event  of  his  having  escaped  the  storm, 
the  probability  of  the  last  named  event  must  be 
first  ascertained.  If  this  be  found  improbable, 
the  second  event  must  fail ;  but  if  it  be  found 
probable,  the  second  event  may  exist,  and  the 
probability  of  its  existence  may  be  found  by 
the  rule  already  given.  [No.  138.] 

141.  As  nine  ships  out  of  the  twelve  surviv- 
ed the  storm,  the  probability  that  W  escaped 
in  one  of  them  is  &  =  £ •  This  being  suppos- 
ed, the  probability  of  his  having  escaped  the 
second  danger,  since  only  one  third  of  those, 
who  survived  the  storm,  perished,  is  §•  Hence 
the  probability  of  his  having  lived  through 
both  dangers  is  IX|=  &  =  £•  Therefore  it 
is  merely  doubtful  whether  he  survived  both 
calamities.     If  only  i  of  the  crew  survived  the 


108  DEMONSTRATIVE    REASONING. 

second  danger,  then  his  escape  would  be  im- 
probable ;  for  f-  X  i  =  TV  If  only  two  out  of 
the  twelve  ships  were  lost,  and  consequently  ten 
had  escaped  the  first  danger,  and  §  of  the  crew 
had  escaped  the  second  danger,  as  above,  then 
the  probability  of  his  entire  survival  would  be 
t§  X  §  =  U  =  I ;  a  slight  probability.* 


CHAPTER   SEVENTH. 

GENERAL    DESCRIPTION    OF    DEMONSTRATIVE    REASONING. 

142.  The  general  nature  of  demonstrative 
reasoning  has  already  been  explained,  in  point- 
ing out  the  circumstances,  which  distinguish  it 
from  moral,  or  probable  reasoning.  [See  No. 
87  to  93.]  It  has  generally  been  admitted, 
that  demonstration  can  be  employed  only  about 
such  truths  as  have  been  termed  necessary,  the 
subjects  of  which  are  not  supposed  to  have  any 
real  existence,  but  to  be  abstractly  conceived 
by  the  mind.  All  created  beings  depend  on 
the  will  of  their  Creator.  Their  existence, 
their  properties,  and  of  course  the  relations, 
subsisting  among  those  properties,  are  contin- 

*  Demoivre,  Doctrine  of  Chances,  Introduction.     Kirwan,  Logick. 
part  ill.  ch.  7. 


DEMONSTRATIVE    REASONING.  109 

gent,  and  perpetually  varying.  Our  reasoning 
on  these  must  be  grounded  on  the  observation 
of  our  senses  ;  and  the  conclusions,  which 
we  make,  are  liable  to  be  uncertain.  But 
demonstrative  reasoning,  being  grounded  on 
exact  and  adequate  definitions,  and  proceed- 
ing by  the  successive  application  of  general 
propositions,  which  have  an  intuitive  agree- 
ment with  each  other,  affords  satisfaction  in 
every  step  ;  and  the  mind  advances  to  the 
conclusion  with  the  fullest  assurance  of  cer- 
tainty. 

143.  Demonstration  is  best  adapted  to  the 
exact  sciences  of  number  and  quantity.  Arith- 
metick  and  geometry  possess  many  important 
advantages  with  respect  to  this  method  of  rea- 
soning. Their  terms  are  free  from  all  ambi- 
guity. Their  first  principles  are  simple  and 
obvious.  The  subjects,  about  which  they  are 
conversant,  are  wholly  independent  of  things 
in  actual  existence,  and  capable  of  being  per- 
fectly defined.  The  properties,  belonging  to 
these  subjects,  and  their  various  relations,  are 
necessary  and  immutable.  These  circumstan- 
ces impart  to  mathematical  demonstrations  a 
clearness  and  force,  which  cannot  be  obtained 
10 


110  DEMONSTRATIVE    REASONING. 

in  other  sciences.  For  these  reasons  many 
have  maintained,  that  demonstrative  reason- 
ing can  be  used  only  within  the  precincts  of 
mathematicks.  Many  others  have  controvert- 
ed this  position  ;  and  have  contended,  that 
this  method  may,  at  least  occasionally,  be 
employed  in  other  sciences. 

144.  Mr.  Locke  advanced  the  opinion,  that 
moral  subjects  are  as  susceptible  of  demonstra- 
tion as  mathematical.  His  reason  for  this 
opinion  is  thus  stated  in  his  Essay  on  the 
Understanding  :*  "The  precise,  real  essence 
"of  the  things,  moral  words  stand  for,  may 
"  be  perfectly  known  ;  and  so  the  congruity  or 
"  incongruity  of  the  things  themselves  be  cer- 
"  tainly  discovered  ;  in  which  consists  perfect 
"knowledge."  He  adds,  "definition  is  the 
"only  way  whereby  the  precise  meaning  of 
"  moral  words  can  be  known  ;  and  yet  a  way, 
"  whereby  their  meaning  may  be  known  cer- 
"  tainly,  and  without  leaving  any  room  for 
"  contest."  In  another  placet  he  says,  "  the 
"relation  of  other  modes  may  certainly  be 
"  perceived,  as  well  as  those  of  number  and 

*  Book  iii.  ch.  11.  sect.  16. 
t  Book  iv.  ch.  3.  sect.  18. 


DEMONSTRATIVE    REASONING.  Ill 

44  extension ;  and  I  cannot  see  why  they  should 
"  not  also  be  capable  of  demonstration,  if  due 
11  methods  were  thought  on  to  examine  or  pur- 
14  sue  their  agreement  or  disagreement." 

145.  Dr.  Rcid  distinguishes  demonstrative 
reasoning  into  two  kinds,  which  are  metaphy- 
sical and  mathematical.  "  In  metaphysical 
44  reasoning,"  he  observes,  44  the  process  is 
44  always  short.  The  conclusion  is  but  a  step 
44  or  two,  seldom  more,  from  the  first  principle 
44  or  axiom,  on  which  it  is  grounded  ;  and  the 
44  different  conclusions  depend  not  one  upon 
44  another.  It  is  otherwise  in  mathematical 
44  reasoning.  Here  the  field  has  no  limits.  One 
44  proposition  leads  to  another;  that  to  a  third, 
44  and  so  on  without  end.  If  it  should  be  asked, 
44  why  demonstrative  reasoning  has  so  wide 
"  a  field  in  mathematicks,  while,  in  other 
"  abstract  subjects,  it  is  confined  within  very 
44  narrow  limits ;  I  conceive  this  chiefly  owing 
44  to  the  nature  of  quantity,  the  object  of  math- 
44  ematicks."* 

146.  Demonstration,  in  the  customary  sense 
of  the  term,  appears  not  to  be  absolutely  cir- 
cumscribed by  the  narrow  limits  of  a  single 

*  Essays  on  the  Intellectual  Powers,  essay  vii.  ch.  1. 


112  DEMONSTRATIVE    REASONING. 

science.  Wherever  the  subjects  of  our  reason- 
ing are  independent  on  the  existence  of  thmgs, 
and  are  of  a  nature  to  afford  exact  definitions 
and  general  propositions  of  undoubted  certain- 
ty, there  this  method  of  reasoning  may  be 
employed.  And  it  appears  unnecessary  to 
concede,  that  these  elements  of  demonstration 
are  no  where  to  be  found,  except  in  the  sci- 
ence of  mathematicks. 

147.  Professor  Scott,  speaking  of  Dr.  Reid's 
division  of  demonstrative  reasoning,  says;  "  It 
"  evidently  cannot  be  meant  by  Dr.  Reid,  that 
"  metaphysicks  is  a  science  demonstrable  in  all 
"  its  parts,  like  mathematicks.  He  was  too 
•'  well  acquainted  with  the  general  uncertainty 
"  of  metaphysical  speculations  to  have  advanc- 
"  ed  such  an  opinion.  If  then  he  asserts  only, 
"  that  several  metaphysical  truths  admit  of 
"  demonstration,  the  same  ought  doubtless  to 
"  be  said  of  physicks,  many  of  the  reasonings 
"  of  which  have  at  least  as  much  of  demonstra- 
"  tive  certainty  as  any  of  the  speculations  of 
"  metaphysicks.  The  truth  appears  to  be, 
"  that  every  branch  of  science  may  occasional- 
"  ly  assume  the  demonstrative  form.  The  ex- 
"  istence  of  a  Deity,  the  immateriality  of  the 


DISTINCTIONS    OF    REASONING.  113 

1  human  soul,  and  other  moral  or  metaphysical 

*  truths,  have  perhaps  been  as  fairly  demon- 
'  stratcd  as  the  Pythagorean  proposition,  or 
1  the  parabolick  motion  of  projectiles.  But 
'  some  sciences  are  much  more  susceptible  of 
i  this  kind  of  proof  than  others  ;  physicks 
'  admitting  much  more  of  demonstration  than 
'  metaphysicks,  or  morals.  Of  all  the  sciences, 
'  mathematicks  is  that,  which  admits  the  most 

*  largely  of  demonstration.  Its  first  principles 
'  are  so  certain,  so  definite,  and  clear ;  and  its 
4  manner  of  proof  so  accurate  and  legitimate, 
'  that  it  may  fairly  be  called  a  completely  de- 
'  monstrative  science,  and  the  only  one,  which 
1  is  justly  entitled  to  that  name."* 


CHAPTER   EIGHTH. 

DISTINCTIONS    OF    REASONING. 

148.  Reasoning  is  further  distinguished 
into  that,  which  is  a  priori,  and  that,  which  is 
a  posteriori.  Reasoning  a  priori  is  that,  which 
deduces  consequences  from  definitions  formed, 
or  principles  assumed ;  or  which  infers  effects 
from  causes  previously  known.     The  books  of 

*  Elem.  of  Tntell.  Phil.  chap.  8.  sect.  4. 

10* 


114  DISTINCTIONS    OF    REASONING. 

mathematicks  afford  numerous  instances  of 
conclusions  legitimately  drawn  from  definitions 
and  assumed  principles.  We  also  reason  a 
priori  whenever  we  judge  of  effects  from  a 
knowledge  of  the  causes,  which  produce  them. 
Thus  we  infer,  that  an  eclipse  of  the  sun  and 
an  eclipse  of  the  moon  can  never  happen 
within  twelve  days  of  each  other,  from  our 
knowledge  of  the  causes,  which  occasion  those 
phenomena. 

149.  Reasoning  a  posteriori  is  the  reverse  of 
the  former  process.  By  this  we  deduce  causes 
from  effects.  Thus  we  infer,  that  the  earth  is 
spherical  from  its  shadow  on  the  moon  in  a 
lunar  eclipse  ;  and  we  infer  the  being  of  a  God 
from  our  own  existence  and  that  of  the  objects 
around  us.  All  reasoning  concerning  the 
properties  and  laws,  both  of  mind  and  body, 
proceeds  on  this  principle.  It  is  only  by  a 
careful  observation  of  facts,  that  the  laws, 
which  regulate  them,  can  be  discovered. 

150.  Another  distinction  of  reasoning  is 
into  direct  and  indirect.  The  reasoning  is  di- 
rect, when  the  proofs  are  so  applied,  as  to  show 
immediately  the  agreement  or  repugnancy  between 
the  subject  and  predicate  of  the  proposition  in 


DISTINCTIONS    OF    REASONING.  115 

question.  In  indirect  reasoning,  the  argu- 
ments, which  we  employ,  are  not  intended  pri- 
marily to  show  the  relation  between  the  terms 
of  the  proposition,  whose  truth  we  would 
establish  ;  but  to  prove  the  falsehood  or  absurd- 
ity of  the  proposition,  to  which  it  is  opposed. 
This  method  may  be  adopted,  whenever  it  is 
manifest,  that  the  proposition,  which  we  allege, 
or  its  contrary,  must  be  true.  We  may  then 
prove  the  impossibility  of  the  contrary  propo- 
sition ;  or  we  may  show,  that  a  manifest  ab- 
surdity must  follow  from  admitting  it  ;  and 
in  either  case  we  establish  the  truth  of  our 
original  proposition.  The  former  course  is 
usually  called  a  proof  per  impossibile ;  and  the 
latter,  a  reductio  ad  absurdum. 

151.  Mathematicians  make  frequent  use  of 
indirect  reasoning.  Thus,  Euclid  proves,  by 
an  indirect  course,  that,  "if  two  circles  touch 
"  each  other  internally,  they  cannot  hare  the 
"  same  centre."  He  first  supposes  the  contra- 
ry to  be  true,  namely,  that  the  two  circles  have 
the  same  centre  ;  and  no  third  supposition  can 
be  made ;  for  they  must  either  both  have  the 
same  centre  or  not.  He  then  demonstrates  the 
impossibility  of  the  case  assumed  :  and  thence 


116  SYLLOGIST1CK    REASONING. 

infers  the  truth  of  the  proposition,  which  he 
first  asserted.  So  moralists  prove  the  exist- 
ence of  an  all-wise  and  powerful  Creator,  by 
tracing  the  absurdities,  which  the  contrary 
supposition  involves. 

152.  Another  form  of  indirect  reasoning,  in 
frequent  use,  is  denominated  reasoning  a  forti- 
ori. This  consists  in  deducing  a  proposition, 
as  true,  from  less  obvious  propositions,  embrac- 
ed by  the  same  general  principles.  Thus,  if 
the  felon,  who  robs  on  the  highway,  deserves 
the  punishment  of  death,  this  retribution  is  due 
a  fortiori  to  the  wretch,  who  has  committed 
parricide. 


CHAPTER   NINTH. 

GENERAL    DESCRIPTION    OF    SYLLOGISTICK    REASONING. 

153.  All  reasoning  proceeds  by  comparison  ; 
and  two  comparisons  are  necessary  to  enable 
us  to  make  a  conclusion.  The  subject  and 
predicate  of  the  proposition  to  be  proved  must 
be  separately  compared  with  some  third  term, 
or  common  measure  ;  and  from  these  compari- 
sons we  infer  their  agreement  or  repugnancy, 


SYLLOGISTICK    REASONING.  117 

This  process,  when  expressed   in   words,  con- 
of  three  propositions,  and  has  been  termed 
syllogism* 

154.  Syllogism  was  regarded,  for  many  cen- 
turies, as  the  only  sure  instrument  of  reasoning  ; 
and  skill  in  the  use  of  it   as  the  highest  ac- 
complishment, which  the  mind  can  possess.     It 
derived   its  celebrity  from   the   talents  and  in- 
dustry of  Aristotle,  who  traced  and  analyzed  its 
principles,  subjected  it  to  laws,  and  exhibited 
it  in  all  the  variety  of  modes  and  figures,  into 
which  it  could   be  moulded.     Since  the  time 
of  that  philosopher,   the  name   syllogism  has 
usually  been  employed  to  denote  an  argument, 
framed  according  to  certain  technical  rules  of 
art.    But  it  is  sometimes  used  in  a  larger  sense, 
to  imply  any  process  of  reasoning  from  more 
general  to  less  general,  in  opposition   to  the 
principle  of  analytical  induction.    '  In  this  sense, 
it  will  apply  to  mathematical  reasoning;    for 
all  demonstrations  in  this  science  proceed  on 
this    fundamental    principle   of  the   syllogism, 
that  whatever  may    be  affirmed    of  any  genus 
may  be  affirmed  of  all  the  species  included  un- 
der it. 

*  TvWoyiopbs,  compiiiaiio,  a  (7vXAoy<£o/iai,  colligo,  ratiocinor,  compido. 


118  SYLLOGISTICK    REASONING. 

155.  Syllogism  and  induction  proceed  in 
opposite  directions.  Induction,  as  has  already 
been  observed,  begins  with  individual  objects, 
as  they  exist  in  nature,  and  ascends  by  succes- 
sive steps  to  the  most  general  truths.  Syllo- 
gism begins  where  induction  terminates.  It 
commences  with  some  universal  proposition, 
and  follows  back  the  footsteps  of  the  former 
process,  transferring  at  each  stage  the  predi- 
cate of  the  more  general  to  the  less  general 
rank  of  beings  ;  or,  in  other  words,  predicating 
the  genus  of  the  species,  and  the  species  of 
the  individual. 

156.  The  difference  ol  these  methods  may 
be  shown  by  the  following  example.  We  ob- 
serve that  the  individual  people  of  our  acquaint- 
ance are  constantly  dying  around  us  ;  that  men 
rarely  live  to  the  age  of  a  hundred  years,  and 
that  the  former  generations  are  wholly  swept 
from  the  earth.  From  these  facts  we  infer, 
that  death  is  the  common  lot  of  our  species. 
Observing  also,  that  the  same  fatality  attends 
the  various  species  of  beasts,  birds,  and  insects, 
we  deduce  the  more  general  conclusion,  that  all 
animals  are  mortal.  This  inductive  process,  re- 
versed in  syllogistick  language,  would  run  thus, 


SYLL0G1STICK  REASONING.        119 

All  animals  are  mortal ; 
All  men  are  animals ; 
Therefore  all  men  are  mortal. 

All  men  are  mortal ; 
W.  X.  Y.  are  men  ; 
Therefore  W.  X.  Y.  are  mortal. 

157.  Syllogism  is  employed  with  advantage 
in  communicating  to  others,  in  an  exact  and 
perspicuous  manner,  the  general  principles  of 
science.  It  may  also  be  used  with  success  in 
exposing  the  weakness  of  arguments,  stated  in 
loose  or  figurative  language.  But  it  is  of  no 
service  in  helping  us  to  the  discovery  of  new 
truths.  We  must  know  a  thing  first,  Mr. 
Locke  observes,*  and  then  we  can  prove  it 
syllogistically. 

158.  As  syllogism  operates  wholly  on  gen- 
eral propositions,  and  definitions  previously 
established,  the  justness  of  its  conclusions  must 
depend  ultimately  on  the  accuracy,  with  which 
the  inductive  processes  have  been  conducted. 
"  The  syllogism,"  says  Lord  Bacon,  "  is  form- 
"  ed  of  propositions  ;  propositions,  of  words  ; 
"  and  words  are  the  marks  of  ideas.  If  there- 
"  fore  ideas  themselves,  whichmake  the  ground- 
"work  of  our  reasonings,  are  confused,  and 

*  Essay,  b.  iv.  ch.  17. 


120  REGULAR    SYLLOGISMS. 

"  formed  from  a  hasty  observation  of  things, 
"  the  conclusions,  which  we  make  from  them, 
"  will  be  without  solidity.  The  whole  there- 
"  fore  depends  on  the  accuracy  of  our  induc- 
"  tions."* 


CHAPTER   TENTH. 

OF     RECULAR     SYLLOGISMS. 

159.  The  most  general  division  of  syllogisms 
is  into  single  and  compound.  Of  single  syllo- 
gisms, some  are  regular  and  some  are  irregular. 
A  regular  syllogism  is  an  argument,  consisting 
of  three  projwsitions,  the  last  of  which  is  deduced 
from  the  two  preceding,  and  is  substantially  con- 
tained in  them.     Example  : 

Every  human  virtue  should  be  habitually  practised ; 
Industry  and  temperance  are  human  virtues  ; 
Therefore  industry  and  temperance  should  be  habitually 
practised. 

160.  This  is  a  concise  and  luminous  method 
of  evincing  the  agreement  or  repugnancy  be- 
tween the  subject  and  predicate  of  a  proposi- 

*  "  Sy llogusn:  tfs  ex  propositionibus  constat  ;  propositiones,  ex 
"  verbis  ;  verba  notionum  tesserae  sunt.  Itaque  si  notiones  ipsae, 
"  id  quod  basis  rei  est,  confusae  sint,  et  temere  a  rebus  abstractse, 
,{  nihil  in  iis,  quae  superstruuntur,  est  firmitudinis.  Itaque  spes  est 
u  una  in  inductione  vera."     Novum  Organum,  lib.  i.  aph.  14. 


■  ri.AR    BY]  121 

tion.     A  third  term,  h  mon  relation 

them  both,  Lb  invenl  lied  to  them 

successively,    in    two     distinct     p         ritions. 

These  are  called  •  from,  th- 

tlif  proposed  (p.;  ia  interred,  as  a  conclu- 

:  :  and  its  subject  and  predicate  bj         bei 

parated,  according  a.-  they   w< 

ad   in  the   pi  to  agree,  or  nut.  with 

the  term  introduced.      It  is  obvious,    that,   if 

with  a  third,  they  must 
each  and  that  two  things,  of 

i chick  i  the  other  disagrees,  with 

a  third.  >    with   each  other.      The 

former  of  these  rules  is  the  foundation  of  all 
affirmative  conclusions,  and  the  latter  of  all 
negati 

161.    The  names  of  the  three  propositions 
are  the  .   the   minor,  and  the  conclusion. 

These  ar  of  three  terms,  denomin- 

ated the  major,  the  minor,  and  the  middlt 
Th  .///• ■//  the  ma- 

joi  I  .  because  it  is  the  most  general  :  and 
the    s  m  the    minor   term. 

because  it  is  the  least  general.  These  two  are 
also  denominated  the  extreme*  :   and  the  third 

*  See  note  B.  at  the  end  of  the  book. 
11 


122  REGULAR    SYLLOGISMS. 

term,  introduced  as  a  common  measure  be- 
tween them,  is  called  the  mean  or  middle  term, 
because  its  extension  is  less  than  that  of  the 
major,  and  greater  than  that  of  the  minor  term. 
[See  No.  35.]  This  circumstance  proves  the 
natural  situation  of  the  middle  term  to  be  that 
of  subject  in  the  major  premise,  and  of  predi- 
cate in  the  minor  ;  since  the  predicate  of  a 
proposition  is  never  less,  but  usually  more 
general,  than  the  subject. 

162.  In  forming  the  syllogism,  each  term  is 
taken  twice,  and  no  more.  The  middle  and 
major  terms  constitute  the  major  premise ;  the 
minor  and  middle  terms  the  minor  premise  ;  and 
the  two  extremes,  connected  by  a  copula,  make 
ap  the  conclusion.  The  major  proposition 
must  always  be  universal,  but  may  be  either 
affirmative  or  negative  ;  and  the  minor  prop- 
osition must  always  be  affirmative,  but  may 
be  either  universal  or  particular.*  The  con- 
clusion may  be  either  universal  affirmative, 
universal  negative,  particular  affirmative,  or 
particular  negative. 

163.  In  every  regular  syllogism,  the  major 
proposition  is  placed  first  ;   the   minor  next  ,* 

*  See  note  C,  at  the  end  of  the  book. 


REGULAR    SYLLOGISMS.  123 

;ind  the  conclusion  last ;  as  in  the  following 
example. 

Every  vegetable  is  combustible; 

Every  tree  is  a  vegetable; 

Therefore  every  tree  is  combustible. 

Combustible  is  the  major  term  ;  every  tree  the 
minor  term  ;  and  these  extremes  are  joined  in 
the  conclusion.  Vegetable  is  the  middle  term; 
it  is  subjected  in  the  major  premise,  and  pre- 
dicated in  the  minor.  The  major  premise  must 
always  be  sufficiently  general  to  involve  the 
conclusion  ;  and  must  be  assumed  as  a  truth 
already  known.  It  cannot  be  proved  by  syllo- 
gism. This  instrument  teaches  only  how  to 
make  a  legitimate  inference  of  one  proposition 
from  another. 

164.  The  truth,  proved  by  the  preceding 
example,  is,  that  trees  are  combustible.  The 
major  premise,  namely,  every  vegetable  is  com- 
bustible, is  first  assumed  on  the  ground  of  ex- 
perience and  observation.  The  minor  premise 
barely  asserts  the  fact,  that  trees  belong  to  the 
class  of  vegetables.  Now  if  it  be  certain,  that 
combustion  belongs  universally  to  vegetables, 
and  that  trees  are  included  in  that  class  of 
things,  it  must  of  necessity  follow,  that  every 


124  REGULAR    SYLLOGISMS. 

tree  is  combustible  ;  for  it  is  a  primary  law  of 
syllogistick  reasoning,  that  whatever  may  be 
affirmed  of  any  general  term,  may  be  affirmed 
of  every  species  and  individual  included  within 
its  extension. 

165.  In  the  regular  syllogism,  each  step  of 
(he  reasoning  process  is  distinctly  expressed  ; 
but,  in  familiar  language,  one  part  is  frequent- 
ly omitted,  which  may  be  readily  found  by 
examining  the  grounds,  on  which  the  judgment 

is  formed.     Thus, 

No  language  is  perfect ; 
Because  it  is  a  human  invention. 

Perfection  is  here  denied  of  language,  for  no 
other  assigned  reason,  than  because  it  is  a 
human  invention.  But  there  is  a  latent  prop- 
osition, which  is  the  real  ground  of  the  judg- 
ment, and  must  therefore  have  been  distinctly 
contemplated  by  the  mind,  namely,  no  human 
invention  is  perfect.  Let  this  proposition  be 
subjoined  to  the  other  two,  and  the  argument 
will  stand  thus ; 

No  language  is  perfect ; 
Because  it  is  a  human  invention  ; 
And  no  human  invention  is  perfect. 

This  is  the  regular  syllogism  reversed  ;  which, 
rectified,  will  stand  thus  ; 


REGULAR    SYLLOGISMS.  125 

No  human  invention  i    p  ufect; 
Every  language  is  a  human  invention; 

Therefore  no  language  is  perfect. 

166.  Every  assertion,  accompanied  by  a 
reason  why  it  is  made,  contains  the  elements 
of  a  'gism,  namely,  the  major,  minor,  and 
middle  terms.  Every  such  assertion,  made  in 
the  familiar  form  of  language,  may  he  trans- 
ferred to  a  regular  syllogism,  by  observing  the 
following  rule  :  First,  distinguish  the  reason, 
on  which  the  attribute  of  the  given  proposition 
is  affirmed  or  denied  of  its  subject,  and  this 
will  be  the  middle  term  of  the  syllogism.  Let 
this  be  taken,  in  its  most  enlarged  sense,  for 
the  subject  of  a  proposition,  to  which,  for  a 
predicate,  unite  the  attribute  of  the  asserted 
proposition,  and  the  major  premise  will  be 
formed.  Next,  to  form  the  minor  premise,  we 
have  only  to  predicate  the  middle  term,  already 
found,  of  the  subject  of  the  asserted  proposition. 
The  original  proposition,  without  the  reason, 
before  annexed  to  it,  will  constitute  the  con- 
clusion of  the  syllogism. 

167.  For  example,  Dr.  Johnson  says  of  en- 
vy, "  It  is,  above  all  other  vices,  inconsistent 
"  with  the  character  of  a  social  being,  because 

11  * 


126  REGULAR    SYLLOGISMS. 

"  it  sacrifices  truth  and  kindness  to  very  weak 
"  temptations."  Sacrifices  truth  and  kindness  to 
very  weak  temptations  is  the  reason,  why  envy 
is  pronounced,  above  all  other  vices,  inconsist- 
ent with  the  character  of  a  social  being.  This, 
then,  must  form  the  middle  term  of  the  syllo- 
gism. But  as  this  collection  of  words  repre- 
sents an  attribute,  and  not  a  person  or  thing 
really  existing,  it  cannot  be  enlarged,  so  as  to 
become  the  subject  of  a  general  proposition,  by 
simply  placing  before  it  one  of  the  common 
signs  of  universality,  all,  every,  or  each  ;  it 
must  be  preceded  by  some  universal  sign  of 
a  different  sort,  as  whatever,  that  which,  or  the 
like.     Thus ; 

That  which  sacrifices  truth  and  kindness  to  very  weak 
temptations  is,  above  all  other  vices,  inconsistent  with  the 
character  of  a  social  being  ;  , 

Envy  sacrifices  truth  and  kindness  to  very  weak  temp- 
tations ; 

Therefore  envy  is,  above  all  other  vices,  inconsistent 
with  the  character  of  a  social  being. 

In  this  manner  may  the  simple  elements  of 
reasoning,  however  obscured,  in  any  instance, 
by  rhetorical  language,  or  complicated  forms 
of  speech,  be  easily  collected,  and  exhibited  in 
a  regular  syllogism. 


REGULAR    SYLLOGISMS.  127 

168.  As  the  major  proposition  of  a  syllogism 
must  always  be  universal,  the  middle  term,  as 
the  subject  of  this  proposition,  must  be  taken 
in  a  universal  sense.  Every  middle  term  must 
represent  either  some  class  of  persons  or  things, 
or  else  some  attribute  common  to  a  whole  class 
of  beings.  If  the  middle  term  denote  persons 
or  things,  something  must  be  asserted,  hypo- 
thetically,  in  the  major  proposition,  to  agree 
with;  or  to  be  repugnant  to,  that  whole  class  of 
beings  ;  and  in  this  class  the  minor  term  must 
be  included  ;  which  it  is  the  sole  business  of 
the  minor  proposition  to  affirm.  In  the  conclu- 
sion, wTe  apply  to  the  minor  term,  separately, 
the  same  predicate,  which  was  applied  to  it  in 
the  major  proposition,  in  connexion  with  the 
whole  class  of  things,  to  which  it  belongs. 

169.  If  the  middle  term  express  an  attri- 
bute, it  must  be  asserted  in  the  major  propo- 
sition, that,  to  whatever  person  or  thing  the 
attribute,  forming  the  middle  term,  can  be  as- 
cribed, the  major  term  may  be  ascribed  also. 
In  the  minor  proposition,  the  attribute,  which 
forms  the  middle  term,  is  declared  applicable 
to  the  minor  term.  In  the  conclusion,  the 
agreement  or  repugnancy,  which  was  before 


128  REGULAR    SYLLOGISMS. 

admitted  between  the  middle  and  major  terms, 
ist  be  also  admitted  between  the  major  and 
ior  terms. 

170.    Any  regular  syllogism  may  be  reduced 
liliar  form  of  reasoning,  by  the  follow  - 
:    First,  state  the  conclusion,  omitt 
illative  therefore;  then,  subjoin  the  middle 
i  together  with  the  minor,  or  some  pronoun 
as  its  substitute,  preceded  by  some  causal  par- 
is  .since,  for,  or  because.     For  example. 

Every  animal,  possessing  wings  and  feathers,  is  a  bird  ; 
An  ostrich  is  an  animal,  possessing  wings  and  feathers, 

;>_'  an  ostrich  is  a  bird. 

This  syllogism  may  be  thus  expressed  in  the 
familiar  form  of  reasoning  ; 

An  ostrich  is  a  bird  ; 

Because  it  has  wings  and  feathers. 

171.  Each  of  the  preceding  syllogisms  con- 
cludes with  a  universal  proposition.  The  con- 
clusions of  the  four  following  examples  are  of 

different  kinds. 

I. 

Whoever  disregards  the  rights  of  his  fellow  beings,  de- 
serves the  detestation  of  mankind  ; 
Tyrants  disregard  the  rights  of  their  fellow  beings  ; 
Therefore  tyrants  deserve  the  detestation  of  mankind. 


• 


REGUL  kB    SI  LLOGISM8.  129 

II. 
Th«_-\\    vrho    subvert    the    foundations    of    morality    and 

religion,  ou^ht  not  to  be  r  1  ; 

foundations  of  morality  and  religion  ; 
Therefore  ;•'  bt  not  to  be  respect 

III. 

.   which  can  live  in   more   elements  than 
one,  is  an 
Some  animals  can  live  in  more  elements  than  one; 
Therefore  some  animals  are  amphibio 

IV. 

!ute  habits  can  be  a  safe  companion  ; 
roved  minds   are  dissolute  in  their 
habi'-  ; 
Therefore  some  persons  of  improved  miuds  are  not  safe 
companio; 

The  conclusion  of  the  first  syllogism  is  a 
universal  affirmative  proposition  ;  that  of  the 
b  e  c  ond,  a  _  .  *  i  v  e  ;  t  h  a  t  of  t  h  e  t  b  i  r  d . 

a  particular  affirmative  :  and  that  of  the  fourth, 
a  particular  negative.  These  are  all  the  kinds, 
into  which  propositions  are  distinguished,  in 
reference  to  quantity  and  quality.* 

•  Comrarn  systems  of  Logick.     Coliard.  Logick.  part  i.-.  ch.  4 


;.>0  IRREGULAR    SYLLOGISMS. 

CHAPTER   ELEVENTH. 

ENTIIYMEMES. 

172.  Besides  the  regular,  categorical  syllo- 
gism, described  in  the  preceding  chapter,  there 
are  some  other  kinds  of  single  syllogisms,  which 
have  different  degrees  of  irregularity  in  their 
construction.  Among  these  may  be  placed 
the  enthymeme,  which  is  an  abridged,  or  de- 
fective syllogism,  consisting  of  the  conclusion 
and  only  one  of  the  premises  ;  the  other  being 
suppressed,  as  too  obvious  to  need  insertion. 
It  is  of  very  general  use,  both  in  writing  and 
conversation. 

173.  Which  of  the  premises  is  omitted  in 
any  instance  may  be  known,  by  the  following 
rule  :  (If  the  subject  of  the  conclusion  be  ex- 
pressed in  the  given  premise,  or  proposition, 
containing  the  reason,  the  major  premise  is 
omitted  ;  if  the  predicate  of  the  conclusion  be 
expressed,  the  minor  premise  is  wanting.     Thus, 

Whatever  tends  to  subvert  the  civil  government  should 

be  deprecated ; 
Therefore  civil  dissensions  should  be  deprecated. 

Christianity  teaches  the  way  to  future  happiness ; 
Therefore  it  should  be  diligently  sought. 


IRREGULAR    SYLLOGISMS.  131 

The  minor   premise  is  omitted  in  the 

ample,  and  the  major  in  the  second.     Let  these 

be  supplied,  and  the  syllogisms  will  be  complete. 

Whatever  tends  to  subvert  the  civil  government  should  be 

deprecated  ; 
Civil  dissensions  tend  to  subvert  the  civil  government; 
Therefore  civil  dissensions  should  be  deprecated. 

That  knowledge,  which  teaches  the  way  to  future  happi- 
ness, should  be  diligently  sought; 
Christianity  teaches  the  way  to  future  happiness; 
Therefore  Christianity  should  be  diligently  sought. 

174.  Enthvmemcs  may  be  expressed  in 
various  ways,  and  have  sometimes  been  dis- 
tinguished into  several  kinds.  Those  are  the 
most  regular,  which  conform  to  the  syllogistick 
order.  In  these  the  conclusion  is  placed  after 
the  proposition,  which  contains  the  proof;  and, 
by  supplying  the  omitted  proposition,  the  syl- 
logism is  rendered  perfect,  without  any  other 
alteration.  But,  in  familiar  conversation,  it  is 
more  common  to  express  the  conclusion  first, 
and  then  to  subjoin  the  reason,  on  which  it  is 
grounded,  preceded  by  a  causal  particle.     As, 

Enthusiasm  should  be  avoided ; 
Because  it  leads  us  astray  from  reason. 


132  IRREGULAR    SYLLOGISMS. 

They,  who    deny  a   future    state    of   retribution,  are   in 
error ; 

For  they  deny  the  doctrine  of  the  Bible. 

175.  Although  the  conclusion  be  placed 
after  the  reasoning  proposition,  still  the  enthy- 
meme  will  not  be  regular,  unless  the  syllogis- 
tick  language  and  arrangement  be  employed. 
The  following  sentence  is  an  enthymeme  of 
this  sort : 

"  Since  it  is  the  understanding,  that  sets  man  above  the 
"  rest  of  sensible  beings,  and  gives  him  all  the  ad- 
"  vantage  and  dominion,  which  he  has  over  them  ; 

"  It  is  certainly  a  subject,  even  for  its  nobleness,  worth 
"  our  labour  to  inquire  into."* 

Each  of  these  enthymemes  contains  the  ele- 
ments of  a  syllogism,  namely,  the  major,  minor, 
and  middle  terms  ;  which  may  be  easily  dis- 
tinguished. The  suppressed  propositions  are 
readily  supplied  by  the  mind  ;  and  the  omis- 
sion of  them  contributes  to  the  brevity  and 
elegance  of  language. 

176.    An  act  of  reasoning   may  be  stated 
hypothetically  ;  thus, 

The  African  slave-trade  should  be  discountenanced ; 
If  it  be  a  violation  of  the  natural  rights  of  man. 

*  Locke,  Essay,,  Introduction. 


IRREGULAR    SYLLOGISMS.  133 

Here  the  predicate,  discountenanced,  is  not 
applied  to  the  African  slave-trade  absolutely ; 
but  only  on  condition  of  its  being  a  violation 
of  man's  natural  liberty.  Still  the  reasoning 
is  the  same,  as  if  it  were  expressed  in  this 
absolute  form  : 

The  African  slave-trade  is  a  violation  of  the  natural  rights 

of  man  ; 
Therefore  it  should  be  discountenanced  by  all. 

The  judgment  is  formed  in  the  two  cases  by  a 
comparison  of  precisely  the  same  things. 

177.  What  are  here  considered  as  familiar 
enthymemes  have  usually  been  received  as 
compound  propositions,  and  have  been  distrib- 
uted into  different  species,  under  the  heads  of 
causal,  discretive,  and  conditional.  But,  that 
they  cannot  justly  be  regarded  as  mere  prop- 
ositions of  any  sort,  is  evident  from  this,  that 
each  example  contains  two  entire  propositions. 
[See  No.  80.]  It  is  equally  manifest,  that 
they  represent  complete  acts  of  reasoning, 
since  in  each  the  elements  of  a  perfect  syllo- 
gism are  expressed.* 

*  Collard,  Logick,  part.  iv.  ch.  6. 

12 


134  IRREGULAR    SYLLOGISMS. 

CHAPTER   TWELFTH. 

CONDITIONAL    AND    DISJUNCTIVE    SYLLOGISMS. 

178.  A  conditional  or  hypothetical  syllogism 
is  one,  whose  major  proposition  is  conditional. 
Thus, 

If  men  have  vicious  propensities,  they  need  the  restraints 

of  government ; 
But  men  have  vicious  propensities  ; 
^Therefore  they  need  the  restraints  of  government. 

The  major  premise  consists  of  two  entire  prop- 
ositions, which  make  an  enthymeme.  The 
minor  premise  and  the  conclusion  constitute 
another  enthymeme,  expressing  the  same  mean- 
ing as  the  other,  with  only  this  difference,  that 
what  is  stated  hypothetically  in  the  first  is 
expressed  absolutely  in  the  last.  .  The  first 
part  of  the  major,  containing  the  condition,  is 
called  the  antecedent ;  and  the  last,  which  con- 
tains the  conclusion,  the  consequent.  If  the 
antecedent  be  admitted  in  the  minor  premise, 
the  consequent  must  be  admitted  in  the  conclu- 
sion ;  for  the  condition,  stated  in  the  antece- 
dent, must  always  be  such  as  necessarily  to 
require  the  truth  of  the  consequent.  By  the 
same  necessity  it  will  follow,  that,  if  the  conse- 


IRREGULAR    SYLLOGISMS.  135 

quent  be  contradicted  in  the  minor,  the  ante- 
cedent must  be  contradicted  in  the  conclusion. 
Thus, 

If  death  be  an  eternal  sleep,  the  Scriptures  are  not  true ; 
But  the  Scriptures  are  true  ; 
Therefore  death  is  not  an  eternal  sleep. 

179.  In  conditional  syllogisms  then  there  are 
two  ways  of  reasoning,  which  lead  to  certain 
conclusions.  The  first  is  called  arguing  from 
the  position  of  the  antecedent  to  the  position 
of  the  consequent ;  and  the  other,  arguing  from 
the  removal  of  the  consequent  to  the  removal 
of  the  antecedent.  These  are  the  only  modes 
of  true  reasoning  in  this  sort  of  syllogism  ;  for 
we  are  not  at  liberty  to  adopt  the  contrary 
course,  and  argue  from  the  admission  of  the 
consequent  to  the  admission  of  the  antecedent, 
nor  from  the  removal  of  the  antecedent  to  the 
removal  of  the  consequent.  This  will  be  man- 
ifest in  the  following  example  : 

If  W.  were  a  general,  he  would  have  power  ; 
But  W.  is  not  a  general ; 
Therefore  he  has  not  power. 

If  W.  be  a  general,  he  must  be  obeyed ; 
But  W.  must  be  obeyed  ; 
Therefore  he  is  a  general. 


136  IRREGULAR    SYLLOGISMS. 

The  falsehood  of  the  consequent  will  not  fol- 
low from  the  falsehood  of  the  antecedent,  nor 
the  truth  of  the  antecedent  from  the  truth  of 
the  consequent.  The  one  may  be  true,  and 
the  other  may  be  false,  for  different  reasons 
from  those,  which  are  assigned. 

180.    A  disjunctive  syllogism  is  one,   whose 
major  premise  is  disjunctive.     Thus, 

The  world  is  either  self-existent,  or  the  work  of  some 

finite,  or  of  some  infinite  Being  ; 
But  it  is   not  self-existent,   nor   the  work    of  any  finite 

being ; 
Therefore  it  is  the  work  of  an  infinite  Being. 

The  business  of  the  major  proposition  of  this 
syllogism  appears  to  be  to  enumerate  several 
predicates,  of  which  one  only  can  belong  to  the 
subject.  If  then  the  minor  establishes  one  of 
these  predicates,  the  conclusion  must  remove 
all  the  rest ;  or  if,  in  the  minor  premise,  all  the 
predicates  but  one  are  removed,  the  conclusion 
must  establish  that,  which  remains.  This  pro- 
cedure has  been  denominated  arguing  from  the 
assertion  of  one  to  the  rejection  of  the  rest ; 
or,  from  the  denial  of  one,  two,  or  more,  to  the 
establishment  of  the  remainder.  But  the  term 
arguing  is    applied    to    it  without    any   good 


COMPOUND    SYLLOGISMS.  137 

reason,  since  it  is  nothing  more  than  a  formal 
and  circuitous  method  of  stating  a  fact. 


BHAPTER   THIRTEENTH. 

COMPOUND    .  J  LLOGISHS. 

181.  A  compound  syllogism  consists  of  more 
than  three  propositions,  and  may  be  resolved 
into  two  or  more  syllogisms.  Of  these  the  prin- 
cipal kinds  are  the  Epichirema,  Dilemma,  and 
Sorites, 

The  Epichirema  is  a  compound  argument, 
of  which  the  major  and  minor  premises  are  sep- 
arately proved,  before  the  conclusion  is  drawn. 
Example. 

Unjust  laws  endanger  the  stability  of  government ;    for 

they  create  discontent  among  the  people  ; 
Laws,    which   restrain    the   freedom   of   conscience,    are 

unjust  ;    for  they   require   people   to    abandon    their 

dearest  concerns ; 
Therefore  laws,  which  restrain  the  freedom  of  conscience, 

endanger  the  stability  of  government. 

The  major  and  minor  premises,  with  their 
respective  proofs,  form  two  enthymemes,  which 
may  readily  be  reduced  to  regular  syllogisms. 
Discard  these  proofs,  and  a  regular  syllogism 
will  remain. 
12* 


I  03  COMPOUND    SYLLOGISMS. 

182.  The  epiclnrcma  is  much  used  in  con- 
versation, publick  harangues,  and  oratorical 
discourses.  Cicero's  defence  of  Milo  is  an 
argument  of  this  sort.  His  first  position  is,  that 
it  is  lawful  for  one  man  to  kill  another,  who  lies 
in  wait  to  kill  him.  This  he  proves  from  the 
laws  of  nature  and  the  customs  of  mankind. 
His  second  position  is,  that  Clodius  lay  in  wait 
for  Milo,  with  a  murderous  intent  ;  which  he 
proves  by  his  equipage,  arms,  guards,  and 
other  circumstances.  Then  he  infers  the  con- 
clusion, namely,  that  it  was  lawful  for  Milo  to 
kill  Clodius. 

1 83.  The  Dilemma*  is  a  compound  argument, 
ivhich  establishes  a  general  conclusion,  either 
directly  by  proving  its  necessity,  or  indirectly 
by  showing  the  impossibility  or  absurdity  of  its 
contrary,  in  every  supposable  case.     Thus, 

Every  magistrate  must  either  execute  the  laws,  or  suffer 

them  to  be  violated ; 
If  he  execute  them,  he  will  be  hated  by  the  vicious  and 

profligate  : 
If  he  suffer  them  to  be  violated,  he  will  be  hated  by  the 

wise  and  virtuous ; 
Therefore,  every  magistrate  is  exposed  to  hatred  from  his 

fellow  men. 

*  Ah,  bis,  and  Xa/*/?dvw,  capio. 


COMPOUND    SYLLOGISMS.  139 

The  subject  of  the  conclusion  is  first  divided 
into  two  classes,  namely,  those  magistrates, 
who  do,  and  those  who  do  not  execute  the 
laws.  The  attribute,  hatred,  is  then  affirmed 
of  each  class  separately,  and  is  finally  predi- 
cated of  the  whole  subject.  This  dilemma 
may  be  resolved  into  three  regular  syllogisms. 
The  major  premise  and  the  conclusion,  taken 
together,  constitute  a  regular  enthymeme  ;  and 
the  four  intervening  propositions  form  two 
enthymemes,  hypothetically  stated. 

184.  Pyrrho,  the  ancient  sceptick,  asserted, 
that  no  one  can  have  certain  knowledge  of  any 
thing.  One  of  his  friends  reproved  him  in  the 
following  dilemma  : 

You  either  know  what  you  say  to  be  true,  or  you  do  not 

know  it; 
If  you  do  know  it  to  be  true,  that  very  knowledge  proves 

your  assertion  to  be  false,  and  you  do  wrong  to  make 

it; 

If  you  do  not  know  it  to  be  true,  you  do  wrong  to  assert 
it,  since  no  one  has  a  right  to  assert  what  he  does  not 
know  to  be  true  ; 

Therefore,  in  either  case,  you  do  wrong  to  assert,  that  no 
one  can  have  certain  knowledge  of  any  thing. 

185.  A  dilemma  is  a  form  of  argument 
frequently  employed  both  in  moral  and  math- 


140  COMPOUND    SYLLOGISMS. 

ematical  reasoning.  The  geometrician  adopts 
this  method,  when,  in  order  to  prove  the 
equality  of  two  lines  or  angles,  he  first  assumes, 
that,  if  they  are  not  equal,  one  must  be  either 
greater  or  less  than  the  other  ;  and,  having 
removed  both  these  suppositions,  he  thence  in- 
fers, that  the  proposed  lines  or  angles  are  equal. 
186.  In  order  to  understand  fully  the  prin- 
ciple of  reasoning  in  a  dilemma,  it  is  necessary 
to  consider  the  major  premise  as  conditional, 
the  first  part  of  which  is  commonly  omitted,  to 
wit,  the  antecedent,  which  consists  of  a  general 
assertion,  conditionally  made,  which  it  is  the 
object  of  the  dilemma  to  disprove.  What 
usually  appears  as  the  major  premise,  is  only 
the  consequent  of  this  member,  consisting  of  an 
enumeration  of  all  the  suppositions,  of  which 
the  subject  will  admit.*  If  then  all  these  sup- 
positions be  rejected  in  the  minor  premise,  the 
antecedent  will  of  necessity  be  rejected  in  the 
conclusion.     This  reasoning  proceeds  univer- 

*  By  supplying  the  antecedent  in  the  example  first 
stated,  the  major  premise  will  stand  thus  : 

If  all  magistrates  be  not  exposed  to  the  hatred  of  their  fellow 
men,  it  is  either  because  they  execute  the  laws,  or  suffer  them  to  be 
violated. 


COMrOUND    SYLLOGISMS.  141 

sally  from  the   removal  of  the  consequent  to 
the  removal  of  the  antecedent. 

187.  A  dilemma  may  be  defective  in  two 
ways  ;  first,  when  the  conditions  are  not  ac- 
curately stated  in  the  major  premise;  secondly, 
when  the  argument  may  he  retorted  with  equal 
force  on  him,  who  offers  it.  A  remarkable 
instance  of  the  retort  of  a  dilemma  happened 
in  the  singular  controversy  between  Protagoras 
and  Euathlus.  The  former  engaged  to  teach 
the  latter  the  art  of  pleading  for  a  stipulated 
reward,  one  moiety  of  which  was  to  be  paid 
in  band,  and  the  other  when  the  pupil  gained 
his  first  cause  at  court.  After  a  short  time 
Protagoras  sued  Euathlus  for  the  remaining 
moiety  of  the  money,  and  made  use  of  this 
dilemma  : 

The    case  must    be  decided    either   in    my  favour  or   in 

yours ; 
If  it  is  decided  in  my  favour,  the  sum  will  be  due  to  me 

according  to  the  sentence  of  the  judge  ; 
If  it  is  decided  in  your  favour,  it  will  be  due  to  me  by 

virtue  of  our  contract ; 
Therefore,  whether  I  gain  or  lose  the  cause,  I  shall  obtain 

the  reward. 

Euathlus  thus  retorted  the  dilemma. 


142  COMPOUND    SYLLOGISMS. 

I  shall  either  gain  the  cause,  or  lose  it ; 

If  I  gain  the  cause,  nothing  will  be  due  to  you  according 

to  the  sentence  of  the  judge  ; 
If  I  lose  the  cause,  nothing  will  be  due  to  you  according 

to  our  contract ; 
Therefore  in  neither  case  shall  I  pay  you  the  reward. 

Sometimes  the  consequent  of  the  major  consists 
of  more  than  two  parts,  and  then  the  syllogism 
is  called  a  trilemma,  tesseralemma,  and  so  on. 

188.  The  Sorites*  is  an  irregular,  compound 
argument,  consisting  of  a  series  of  propositions, 
arranged  in  such  a  manner,  that  the  predicate 
of  each  preceding  proposition  forms  the  subject 
of  that  which  follows ;  and  the  concluding  prop- 
osition unites  its  predicate  to  the  subject  of  the 
first.     Thus, 

Avaricious  men  have  many  desires  ; 

They,  who  have  many  desires,  are  in  want  of  many  things ; 
They,  who  are  in  want  of  many  things,  are  unhappy ; 
Therefore  avaricious  men  are  unhappy. 

This  example  contains  the  substance  of  two 
syllogisms,  which  may  be  thus  stated  in  regu- 
lar form  : 

I. 

Those,  who  have  many  desires,  are  in  want  of  many  things ; 

Avaricious  men  have  many  desires ; 

Therefore  avaricious  men  are  in  want  of  many  things. 

*  7.u>p&$,  c&ngeries,  acerims. 


COMPOUND    SYLLOGISMS. 

II. 

Those,  who  want  many  things,  are  unhappy ; 
Avaricious  men  want  many  things  ; 
Therefore  avaricious  men  ore  unhappy. 

189.  Every  sprites  may  be  resolved  into  as 
many  syllogisms  as  it  contains  middle  terms  : 
or  as  it  has  propositions  intervening  between 
the  first  and  the  last.  The  second  proposition 
of  the  sorites  forms  the  major  premise  of  the 
first  syllogism  ;  the  third,  the  major  of  the 
second,  and  so  on.  The  following  example 
may  be  reduced  to  four  syllogisms. 

The  mind  is  a  thinking  substance  ; 

A  thinking  substance  is  a  spirit ; 

A.  spirit  has  no  composition  of  parts  ; 

That,  which  has  no  composition  of  parts,  is  indissoluble ; 

That,  which  is  indissoluble,  is  immortal ; 

Therefore  the  mind  is  immortal. 

190.  A  sorites  may  be  formed  of  hypotheti- 
cal enthymemes,  any  number  of  which  may  be 
so  joined  in  a  series,  that  the  consequent  of 
each  shall  become  the  antecedent  of  the  next 
following  ;  in  which  case,  by  establishing  the 
antecedent  of  the  first,  we  establish  the  conse- 
quent of  the  last ;  or,  by  removing  the  conse- 
quent of  the  last,  we  remove  the  antecedent  of 


144  SOPHISMS. 

the  first.      This  is  manifest  in  the  following 
example  : 

If  men  are  to  be  punished  in  another  world,  God  must  be 

the  punisher ; 
If  God  be  the  punisher,  the  punishment  must  be  just ; 
If  the  punishment  be  just,  the  punished  must  be  guilty  ; 
If  the  punished  be  guilty,  they  could  have  done  otherwise ; 
If  they  could  have  done  otherwise,  they  were  free  agents ; 
Therefore,  if  men  are  liable  to   punishment  in  another 

world,  they  must  be  free.* 


CHAPTER   FOURTEENTH. 

SOPHISMS. 

191.  A  knowledge  of  the  different  kinds  of 
reasoning,  with  their  respective  laws  and 
principles,  is  of  important  use  in  enabling  us 
to  detect  the  sophistry  and  false  reasoning 
employed  in  the  support  of  error.  But  the 
rules  of  logick  are  of  little  service,  till  habit 
has  rendered  them  familiar.  By  frequently 
examining  the  judgments  and  conclusions, 
which  we  have  formed,  and  comparing  them 
with  those  rules  of  procedure,  which  lead  to 
certain  results,  we  insensibly  acquire  the  habit 

*  Common  systems  of  Logick.     Locke,  Essay  on  the  Understand- 
ing, b.  iv.  ch.  17. 


SOPHISMS.  146 

of  conducting  our  intellectual  processes  with 
accuracy,  and  also  a  facility  in  detecting  the 
false  deductions  of  others. 

192.  Arguments,  which  contain  a  latent 
fallacy  under  the  general  appearance  of  cor- 
rectness, arc  denominated  sophisms.  They 
have  been  distinguished  into  various  kinds, 
from  which  the  following  are  selected,  as  those 
which  are  practised  with  the  greatest  frequency 
and  success. 

193.  First.  Ignoreitio  Elenchi,  a  misappre- 
hension of  the  cjuestion.  This  sophism  is  com- 
mitted when  the  arguments  employed  are  of 
a  nature  to  establish  some  other  point,  foreign 
to  the  question  in  debate  ;  as  if  a  person  should 
attempt  to  prove,  that  Alfred  the  Great  was  a 
scholar,  by  affirming  only,  that  he  founded  the 
University  of  Oxford  ;  or,  that  Peter  the  Her- 
mit was  not  a  Christian,  by  proving  that  he 
was  an  ignorant  fanatick.  Neither  of  these 
facts  has  any  necessary  connexion  with  the 
question  to  be  proved  for  a  man  may  be 
a  patron  of  science,  without  being  learned 
himself ;  and  an  ignorant  fanatick  may  be  a 
believer  in  Christianity. 

194.  Disputants  are  frequently  guilty  of  this 
13 


1  46  SOPHISMS. 

fallacy,  when,  in  the  heat  of  controversy,  they 
wander  insensibly  from  the  precise  subject  of 
discussion.  It  is  also  sometimes  committed 
by  design  ;  as  when  a  disputant,  finding  his 
adversary  too  powerful,  or  his  position  un- 
tenable, endeavours  to  gain  an  advantage  by 
altering  the  question.  The  only  effectual 
security  against  this  species  of  sophistry  is,  to 
have  the  subject  accurately  defined,  and  to 
keep  it  steadily  in  view. 

195.  Secondly.  Petitio  Principii,  a  begging 
of  the  question.  This  consists  in  offering,  as 
proof  of  a  proposition,  the  substance  of  that 
proposition  in  other  words.  Thus  a  person 
attempts  to  prove,  that  God  is  eternal,  by  as- 
serting that  his  existence  is  without  beginning 
and  without  end.  The  proof  and  the  question 
to  be  proved  are  substantially  the  same.  This 
fallacy  is  often  practised  in  familiar  con  versa 
tion.  Thus  a  person  asks,  why  opium  induces 
sleep  ?  He  is  answered,  because  it  possesses 
a  soporifick  quality  ;  which  is  equivalent  to 
saying,  that  it  induces  sleep  because  it  indu- 
ces sleep.  So  we  are  told,  that  the  grass 
grows  by  means  of  its  vegetative  power  ;  and 


SOPHI5M3.  147 

that  bodies  tend  to  the  centre,  by  reason  of 
their  gravitation. 

196.  Thirdly.  Arguing  in  a  circle.  This  is 
a  kind  of  sophistry  nearly  related  to  the  pre- 
ceding ;  and  consists  in  making  two  prop' 
tions  reciprocally  prove  each  other.  Thus,  the 
Papists  prove  the  truth  of  the  Scriptures,  bv 
the  infallible  testimony  of  the  church  :  and 
then  establish  the  infallibility  of  the  church, 
by  the  authority  of  the  Scriptures.  The  Ne- 
cessarians practise  this  sophistry,  when  they 
bring  their  hypothesis  to  prove  a  fact,  and 
then  allege  the  fact,  as  proof  of  their  hypoth- 
esis. They  first  assume,  gratuitously,  that  the 
mind  acts  mechanically,  like  the  body  :  and 
that  it  never  can  act.  unless  the  motive,  which 
causes  the  action,  be  greater  than  any  other, 
then  existing  in  the  mind.  Any  particular  vo- 
lition is  then  declared  to  be  necessary,  because 
the  motive,  which  produced  it.  was  the  strong 
est  then  in  the  mind.  But  when  asked  for  the 
proof,  that  this  motive  was  the  strongest,  they 
simply  refer  us  to  the  volition,  which  otherv 
could  not  have  taken  place.  That  is,  the 
volition  was  necessary,  because  it  was  prodoc 
by  the  strongest  motive  ;  and  the  motive  must 


148  SOPHISMS. 

have  been    the  strongest,  because  the  volition 
was  produced. 

197.  Fourthly.  Non  causa  pro  causa;  or 
the  assignation  of  a  false  cause.  From  an  un- 
willingness to  be  thought  ignorant,  people  often 
impose  on  themselves,  and  on  the  credulity  of 
their  fellow  men,  by  assigning,  as  the  cause  of 
an  event,  something,  that  has  no  perceivable 
connexion  with  it.  Among  illiterate  people-, 
rare  occurrences  are  sometimes  thought  to  have 
a  connexion,  barely  on  account  of  their  proxim- 
ity in  time  or  place.  Thus,  should  the  ap- 
pearance of  a  comet  be  followed  by  a  famine, 
pestilence,  or  any  other  grievous  calamity, 
many  people  would  consider  the  comet  as  the 
cause  of  that  calamity.  So,  if  a  person  have 
committed  any  flagrant  crime,  and  shortly 
after  meet  with  some  distressing  evil,  the  for- 
mer is  readily  believed  to  have  been  the  cause 
of  the  latter.  This  sophism  is  practised  by  all 
those  impostors,  who  make  pretensions  to 
supernatural  skill  in  interpreting  enigmatical 
circumstances,  and  in  presaging  future  events, 
from  dreams  and  other  omens  ;  by  which  means 
they  flatter  the  superstition  and  credulity  of 
mankind. 


METHOD.  14!* 

198.  Fifthly.  Another  species  of  sophistry 
is  called  fallacia  accidrntis.  This  consists  in 
pronouncing  concerning  the  general  nature  or 
properties  of  a  thing,  from  some  accidental 
circumstances.  As  when  certain  amusements 
are  condemned,  as  universally  unlawful, because 
they  are  occasionally  carried  to  excess.  So 
religion  has  been  denounced,  as  an  evil  to 
mankind,  because  it  has  sometimes  been  as- 
sumed as  a  cover  for  crimes.  If  a  medicine 
have  operated  unfavourably,  weak  persons  are 
ready  to  reject  it  universally  ;  or,  if  its  good 
effects  have  been  extraordinary,  they  are  ready 
to  adopt  it  in  all  cases  whatsoever.  This  is 
the  great  cause  of  error,  the  substitution  of 
local,  partial,  temporary  connexions,  for  uni- 
versal and  unchangeable.  The  great  remedy 
of  error  is  the  extensive  observation  and  com- 
parison of  particulars,  or  laborious  induction  ; 
and  this  is  the  true  logick. 


CHAPTER   FIFTEENTH. 

DISPOSITION  OR  METHOD. 

199.<iVIethod,  in  logick,  is  a  proper  classic- 
cation  and  arrangement,  of  our  thoughts  on  any 
13* 


150  METHOD. 

subject  either  to  facilitate  the  discovery  of  new 
truths,  or  to  assist  us  in  communicating  to  oth- 
ers truths  already  known  ;  or,  lastly,  to  enable 
us  to  preserve  for  future  use  the  knowledge, 
which  we  have  acquired,  j  The  disposition  best 
adapted  to  the  investigation  of  truth  is  the 
analytick  method ;  which  is  therefore  denomi- 
nated the  method  of  invention  ;  and  that  which 
is  best  suited  to  the  communication  of  knowl- 
edge, is  the  synthetick  method,  which  for  this 
reason  has  been  called  the  method  of  instruc- 
tion. In  both  of  these  methods,  ideas  are 
arranged  in  such  order,  as  to  exhibit  their 
mutual  connexions  and  relations. 

200.  Analysis*  signifies  an  operation,  by 
which  some  process  of  art  is  retraced,  or  some 
compound  subject  is  reduced  to  its  elementary 
parts.  Synthesis^  implies  the  act  of  collecting 
or  putting  together.  By  the  first  we  begin 
with  the  whole,  and  proceed  by  successive 
steps  to  the  parts,  of  which  it  is  composed ;  by 
the  last  we  begin  with  the  parts,  or  the  most 
general  principles,  and  proceed  by  combining 
them  in  due  order  to  make  up  the  whole. 

*  'AvnXuw,  resolvo.  t  'Zvvridwi,  cenjungo,  compono. 


METHOD.  151 

301-     Analysis  and    synthesis   are    terms   of 
frequent  use  in  many  sciences,  bat  they  have 
not  invariably  the  wun<      s   ification  annexed  to 
them.     They  always,  bowev<  r.  d<  i  ote  r>;v" 
pro  .  one  beginning  when    the  other  I 

lates  :   and  they  reciprocally  explain  < 
oth>  r.     Th<  sometimes  both 

with    equal    advantage    in    explaining  the 
thing.     Thus,  the  mechanism  of  a  co 
plicated    machine    may    be  D    by   either 

method.  We  may  do  it  analytically,  by  taking 
.chine,  in  its  entire  state,  and  separating 
in  the  reverse  order  of  their  com- 
bination, carefully  explaining  each  par;  - 
proceed,  till  we  arrive  at  that,  with  which  the 
mechanical  construction  commenced.     Or 

•  •  thetick  method,  and.  begin- 

nio  in  a  state  of  separation, 

ssively  in  their  former  order, 
till  the  combination  is  restored. 

J.  .Most  of  the  improvements  in  the  dif- 
ferent science-  and  arts  have  been  made  by 
analysis.  It  is  by  this  method,  that  thing-  have 
been  ranked  into  classes.  A  species  is  formed 
by  analyzing  individuals  ;  and  a  genu-  by  an- 
alyzing species.     We  practise  the  same  meth- 


152  METHOD. 

od  in  learning  to  read  the  language  of  our 
country.  We  first  acquaint  ourselves  with  the 
letters  of  the  alphabet.  We  next  trace  out 
their  powers,  by  observing  in  what  manner  they 
are  sounded,  as  they  are  variously  combined  in 
syllables  and  words.  In  this  way  we  at  length 
acquire  some  general  rules,  by  which  we  can 
readily  give  to  each  letter  its  appropriate 
sound,  in  any  new  combination.  By  the  same 
method  we  learn  a  foreign  language,  and  uni- 
versal grammar  ;  also  the  philosophy  of  mind, 
anatomy,  chemistry,  botany,  and  other  branches 
of  natural  knowledge. 

203.  The  synthetick  method  is  not  adapted 
to  the  investigation  of  new  truths,  and  is  rarely 
employed  for  that  purpose.  It  is  a  process  of 
composition  ;  and  consists  in  putting  together 
a  number  of  things  in  a  particular  manner,  so 
as  to  accomplish  some  end  proposed.  But  in 
order  to  do  this,  it  is  necessary  for  a  person 
previously  to  possess  the  knowledge,  which  it 
is  the  object  of  the  operation  to  evince.  With- 
out this  knowledge,  he  would  have  nothing  to 
guide  him  in  the  selection  or  arrangement  of  the 
parts  ;  and  would  be  in  the  condition  of  a  man. 
who  should  undertake  to  make  some  very  com- 


METHOD.  153 

pound  medicine,  without  knowing  the  ingredi- 
ents, of  which  it  is  composed.  By  successively 
mixing  substances  of  different  kinds,  and  in 
various  proportions,  directed  only  hy  casual 
circumstances  or  mere  conjecture,  it  is  possi- 
ble for  him  ultimately  to  succeed  ;  but  this 
would  not  be  likely  to  happen,  till  after 
much  waste  of  time  and  many  unsuccessful 
efforts. 

204.  The  superiority  of  the  analytick  over 
the  synthetick  method,  in  the  investigation  of 
now    truths,  is    very    forcibly    shown   by  Mr. 
Stewart  in  the  following  example  :     "  Suppose 
••  ••  Inwty  of  a  very  artificial  construction,  to  be 
"  put    into  my  hands,  as  an   exercise  for  my 
"  ingenuity  ;  and  that  I  was  required  to  inves- 
"  tigate  a  rule,  which  others,  as  well  as  myself, 
"  mi<rht  be  able  to  follow  in  practice,  for  mak- 
"  in^  knots  of  the  same  sort.      If  I  were  to 
-proceed    in    this   attempt    according  to  the 
"  spirit    of  a    geometrical  synthesis,  I   should 
"  have  to  try,  one  after  another,  all  the  vari- 
"  ous  experiments,  which  my  fancy  could  de- 
"  vise,  till  I  had  at  last  hit  upon  the  particular 
"  knot  I  was  anxious  to  tie.     Such  a  process, 
"  however,  would  evidently  be  so  completely 


154  METHOD. 

"  tentative,  and  its  final  success  would  after  all 
"  be  so  extremely  doubtful,  that  common  sense 
"  could  not  fail  to  suggest  immediately  the  idea 
"  of  tracing  the  knot  through  all  the  various 
"  complications  of  its  progress,  by  cautiously 
"  undoing  or  unknitting  each  successive  turn 
"  of  the  thread,  in  a  retrograde  order,  from  the 
"  last  to  the  first.  After  gaining  this  first  step, 
"  were  all  the  former  complications  restored 
"  again,  by  an  inverse  repetition  of  the  same 
"  operations,  which  I  had  performed  in  undoing 
"  them,  an  infallible  rule  would  be  obtained  for 
"  solving  the  problem  originally  proposed."* 

205.  Though  knowledge  is  chiefly  acquired 
by  the  analytick  method,  it  is  most  convenient- 
ly conveyed  to  others  by  the  synthetick.  The 
teacher  uses  one  method,  while  the  pupil 
practises  the  other.  The  synthetick  method 
is  the  most  plain,  concise,  and  regular.  It 
coincides  with  the  order,  in  which  the  useful 
arts  are  practised,  and  most  of  the  business 
of  life  is  transacted.  It  begins  with  the  most 
general  and  obvious  principles,  and  leads  the 
mmd  directly  from  known  truths  to  those 
which    are    unknown.      Instruction   in    every 

■»  Elom.  of  the  Phil,  of  the  Mind,  vol.  ii.  ch-  4.  sect.  3. 


METHOD. 


156 


science  is  given  synthetically.  It  consists  in 
prescribing  rules  more  or  less  general  ;  and 
these  rules  are  nothing  more  than  the  results 
of  analytical  processes  previously  performed. 

206.  The  other  purpose  of  method  is  to 
secure  to  the  mind  a  command  over  the  knowl- 
edge it  has  acquired.  Memory  includes  the 
power  of  treasuring  up  and  preserving  ideas  ; 
and  also  that  of  recalling  them,  when  we  have 
occasions  for  applying  them  to  use.  The  lat- 
ter power  is  usually  termed  recollection.  In 
respect  of  both  these  faculties,  the  burden  of 
memory  is  diminished  by  arranging  the  sub- 
jects of  our  knowledge  under  distinct  heads, 
and  charging  the  memory  with  some  leading 
objects,  only,  in  each  class.  But  the  same  form 
of  arrangement  will  not  equally  contribute  to 
render  the  memory  retentive  and  ready  *  For 
this  reason,  no  plan  can  be  prescribed,  wThich 
will  be  equally  beneficial  to  all. 

207.  People,  engaged  in  the  active  business 
of  life,  are  under  the  necessity  of  carrying  in 
their  minds  a  multitude  of  particulars,  which 
are  of  no  further  use,  than  to  assist  them  in  the 
daily  business  of  their  calling.     To  such  per- 

*  Stewart,  Elem.  vol.  i.  ch.  6.  sect.  2. 


156  METHOD. 

sons  a  prompt  recollection  is  of  the  highest  im- 
portance, as  it  contributes  to  the  despatch  of 
business.  They  will  therefore  seek  an  ar- 
rangement, with  reference  to  this  object ;  and 
the  surest  method  of  effecting  it  is  an  arbitrary 
one,  suggested  by  the  circumstances  of  their 
situation,  all  which  are  of  a  local  and  tempo- 
rary nature.  While  they  continue  their  ha- 
bitual pursuits,  their  thoughts  will  be  succes- 
sively called  up  by  the  objects  offered  to  their 
senses  ;  but  on  changing  their  situation,  so  as 
to  lose  their  familiarity  with  those  objects,  the 
ideas,  which  were  associated  with  them,  must 
in  a  short  time  be  irretrievably  lost. 

208.  A  different  method  of  arrangement  is 
necessary,  to  give  the  mind  a  durable  posses- 
sion of  the  acquisitions  it  has  made.  The 
only  arrangement,  capable  of  effecting  this 
purpose,  is  that,  which  refers  the  truths,  we  are 
solicitous  to  preserve,  to  the  general  principles, 
with  which  they  are  connected.  By  having 
our  ideas  distributed  according  to  this  method, 
reason  can  lend  its  aid  to  the  powers  of  memo- 
ry, by  tracing  the  natural  relations  and  con- 
nexions of  things,  and  thus  deducing  one  truth 
from  another.     Some  sort  of  arrangement  or 


RULES    OF    CONTROVERSY.  157 

other  is  indispensable  to  persons  of  every  con- 
dition ;  otherwise  but  a  small  proportion  of 
the  thoughts,  which  pass  through  the  mind, 
could  by  any  effort  be  recalled. 


CHAPTER   SIXTEENTH. 

RULES  OF  CONTROVERSY. 

209.  From  the  limited  extent  of  human 
knowledge,  and  the  different  points  of  view,  in 
which  the  same  subjects  may  be  contemplated 
by  different  minds,  it  follows  of  necessity,  that 
a  diversity  of  opinions  must  be  entertained  on 
many  subjects  of  speculation.  In  whatever 
manner  people  are  first  led  to  form  their  opin- 
ions, they  are  usually  disposed  to  defend  them 
afterwards  with  zeal  and  pertinacity.  Hence 
arise  controversies  and  disputes,  which  are 
oftentimes  conducted  with  such  intemperate 
and  misguided  zeal,  as  to  inflame  animosities, 
by  which  the  comfort  and  harmony  of  society 
are  impaired. 

210.  These  are  the  worst  fruits  of  contro- 
versy. They  are,  however,  merely  incidental 
effects  ;  and  are  counterbalanced  by  others  of 
an  opposite  character,  and  of  high  importance 

14 


158  RULES    OF    CONTROVERSY. 

to  the  interests  of  truth  and  virtue.  The 
advantages  of  controversy  consist  in  having 
questions  of  difficulty  and  moment  settled  in  a 
satisfactory  manner.  The  principles  of  gov- 
ernment and  law  have  been  immovably  fixed 
by  the  debates,  which  have  passed  in  deliber- 
ative assemblies  and  in  courts  of  justice. 

211.  All  questions,  not  susceptible  of  rigor- 
ous demonstration,  can  be  correctly  settled 
only  by  a  full  and  impartial  comparison  of  the 
reasons  on  both  sides.  This  is  seldom  done, 
with  sufficient  exactness,  by  the  solitary  inves- 
tigation of  an  individual.  Men  rarely  enter 
on  the  examination  of  a  question  wholly  free 
from  the  bias  of  a  previous  opinion  respecting 
it,  which  makes  them  more  solicitous  to  find 
arguments  for  one  side  than  for  the  other. 
It  is  only  when  the  talents  of  different  persons 
are  enlisted,  and  opposite  opinions  are  contend- 
ed for,  that  questions  are  traced  in  all  their 
bearings,  and  the  grounds  of  an  equitable 
decision  are  fully  exhibited. 

212.  The  importance  of  controversy  may  be 
inferred  from  the  use,  which  has  been  made  of 
it,  in  every  period  of  the  world.  It  has  been 
adopted,  as  the  principal  mode  of  transacting 


RULES    OF    CONTROVERSY.  159 

business,  in  the  halls  of  legislation  and  in  courts 
of  justice,  where  questions  of  the  deepest  con- 
cern to  individuals  and  communities  are  decid- 
ed. The  minds  of  youth  have  been  trained 
to  it  in  seminaries  of  education,  where  the 
practice  of  disputation,  in  various  forms,  ha  I 
been  preserved,  as  a  salutary  discipline  of  the 
mental  powers. 

213.  As  controversy,  especially  when  carried 
on  from  motives  of  victory  or  reputation,  is 
liable  to  be  productive  of  evil  rather  than  of 
good,  it  is  incumbent  on  all,  who  engage  in  it, 
from  whatever  motives,  to  observe  rigorously 
those  laws  and  principles,  by  which  the  former 
may  be  avoided  and  the  latter  secured.  The 
following  rules,  sometimes  called  canons  of 
controversy,  have  been  highly  approved  by 
writers  of  learning  and  discernment.* 

214.  Rule  1st.  The  terms,  in  which  the  ques- 
tion in  debate  is  expressed,  and  the  precise  point 
at  issue,  should  be  so  clearly  defined,  that 
there  could  be  no  misunderstanding  respect 
them.  If  this  be  not  done,  the  dispute  is  liable 
to  be,  in  a  great  degree,  verbal.     Arguments 

*  These  rules  are  taken,  with  slight  alterations,  from  the  lectures 
of  Dr.  Hey,  Norrisian  Professor  in  the  University  of  Cambridge. 
They  may  also  be  found  in  Kirwan's  Logick,  vol.  ii. 


160  RULES    OF    CONTROVERSY. 

will  be  misapplied,  and  the  controversy  pro- 
tracted, because  the  parties  engaged  in  it  have 
different  apprehensions  of  the  question. 

215.  Rule  2d.  The  parties  should  mutually 
consider  each  other,  as  standing  on  a  footing  of 
equality  in  respect  to  the  subject  in  debate. 
Each  should  regard  the  other  as  possessing 
equal  talents  knowledge,  and  desire  for  truth, 
with  himself ;  and  that  it  is  possible,  therefore, 
that  he  may  be  in  the  wrong,  and  his  adversary 
in  the  right.  In  the  heat  of  controversy,  men 
are  apt  to  forget  the  numberless  sources  of 
error,  which  exist  in  every  controverted  sub- 
ject, especially  of  theology  and  metaphysicks. 
Hence  arise  presumption,  confidence,  and 
arrogant  language  ;  all  which  obstruct  the 
discovery  of  truth. 

216.  Rule  3d.  All  expressions,  ivhich  are 
unmeaning,  or  without  effect  in  regard  to  the 
subject  in  debate,  should  be  strictly  avoided. 
All  expressions  may  be  considered  as  unmean- 
ing, which  contribute  nothing  to  the  proof  of 
the  question  ;  such  as  desultory  remarks  and 
declamatory  expressions.  To  these  may  be 
added  all  technical,  ambiguous,  and  equivocal 
expressions.     These  have  a  tendency  to  dazzle 


RULES    OF    CONTROVERSY.  161 

and  bewilder  the  inind,  and  to  hinder  its  clear 
perception  of  the  truth. 

217.  Rule  4th.  Personal  reflections  on  an 
adversary  should  in  no  instance  be  indulged. 
Whatever  be  his  private  character,  his  foibles 
arc  not  to  be  named  nor  alluded  to  in  a  con- 
troversy. Personal  reflections  are  not  only 
destitute  of  effect,  in  respect  to  the  question 
in  discussion,  but  they  are  productive  of  real 
evil.  They  obstruct  mental  improvement,  and 
are  prejudicial  to  publick  morals.  They  indi- 
cate in  him,  who  uses  them,  a  mind  hostile  to 
the  truth  ;  for  they  prevent  even  solid  argu- 
ments from  receiving  the  attention,  to  whicl 
they  are  justly  entitled. 

218.  Rule  5th.  No  one  has  a  right  to  accuse 
his  adversary  of  indirect  ?notives.  Arguments 
are  to  be  answered,  whether  he,  who  offers 
them,  be  sincere  or  not,  especially  as  his  want 
of  sincerity,  if  real,  could  not  be  ascertained. 
To  inquire  into  his  motives,  then,  is  useless. 
To  ascribe  indirect  ones  to  him  is  worse  than 
useless  ;  it  is  hurtful. 

219.  Rule  6th.  The  consequences  of  any  doc- 
trine are  not  to  be  charged  on  him,  icho  maintains 
it,  unless  he  expressly  avows  them.     If  an  abs: 

14* 


162  RULES    OF    INTERPRETATION. 

consequence  be  fairly  deducible  from  any  doc- 
trine, it  is  rightly  concluded  that  the  doctrine 
itself  is  false  ;  but  it  is  not  rightly  concluded, 
that  he,  who  advances  it,  supports  the  absurd 
consequence.  The  charitable  presumption,  in 
such  a  case,  would  be,  that  he  had  never  made 
the  deduction ;  and  that,  if  he  had  made  it,  he 
would  have  abandoned  the  original  doctrine. 

220.  Rule  7th.  As  truth,  and  not  victory, 
is  the  professed  object  of  controversy,  whatever 
proofs  may  be  advanced,  on  either  side,  should 
be  examined  with  fairness  and  candour;  and  any 
attempt  to  ensnare  an  adversary  by  the  arts  of 
sophistry,  or  to  lessen  the  force  of  his  reaso?iing, 
by  wit,  cavilling,  or  ridicule,  is  a  violation  of 
the  rules  of  honourable  controversy. 


CHAPTER  SEVENTEENTH. 

RULES  OF  INTERPRETATION. 

221.  To  ascertain  the  true  meaning  of  a 
written  document  is  often  difficult  and  embar- 
rassing, even  when  it  is  of  recent  date  and  in 
our  own  language  ;  but  the  difficulty  is  greatly 
enhanced,  when  the  writing  is  in  a  foreign 
language,  or  has  descended  from  ancient  times. 


RULES    OF    INTERPRETATION.  163 

222.  The  circumstances,  which  aggravate 
the  labour  of  the  interpreter,  are  numerous,  and 
of  various  kinds.  No  branch  of  knowledge  is 
entirely  exempt  from  them  ;  but  they  exist  in 
the  greatest  degree  in  those  sciences,  which 
involve  our  most  important  interests,  both 
sacred  and  civil.  For  this  reason,  principles 
and  rules  of  interpretation  have  been  carefully 
formed  for  developing  the  true  meaning  of  the 
sacred  Scriptures  and  of  legal  instruments. 

223.  The  design  of  interpretation  is  to 
ascertain  the  real  intention  of  the  writer  ;  to 
develope  the  true  meaning  of  his  words,  where 
they  are  obscure  or  ambiguous ;  and  to  deter- 
mine what  was  his  design,  where  his  words  do 
it  but  imperfectly.  The  following  rules  are  of 
a  general  character,  and  may  be  employed 
with  equal  advantage,  in  explaining  writings 
of  every  kind : 

224.  Rule  1st.  The  interpreter  of  a  written 
document  must  have  a  thorough  knowledge  of 
the  language,  in  which  it  is  written. 

225.  Rule  2d.  He  must  possess  an  intimate 
acquaintance  with  the  subject  of  the  writing. 
Many  words  have  different  significations  in 
different  sciences  and  arts  ;  and  the  particular 


?.".ii:    :.-    ::  :i:  ;;  i: .-.: :;>. 

■---:     -  ^;:,  :l      „.;:_:'_-:-;■      e:c  v:„:*:    ::. 

The  true  inte rpr  e ration  of  a 
"".".'  .._  vi  ::..:—  1  .:z:~.  j;  ■;:"  *..:.-: 
c„in;:~:  ;:  .  -  i_:i_:;.  IT..-  :.  e-i'il  :ir  :  ■•vi:  ::' 
mind,  his  temperament,  his  vocation,  and 
especially  his  political  or  r eligiocs  tenets,  may 
bare  had  an  influence,  lor  which  some  allow- 

227.  Rule  4th.  If  the  writing  to  be  interpret- 
•:-:  ':..  ::'  il::-l:  ii*:.:„:  ::_:-::;-:-:  =!:■:]: 
v:v;:-.„:„v  eri..:^i^:  ::!:.=  :ei:  :  Lr.i.:: 
it  has  descended  to  him  as  it  came  from  the 
author,  without  any  corruptions  or  interpola- 
tions  from  other  ban 

-  -      -  " 

be  well  acquainted  with  the  ~  of  the  coon- 

ind  of  th  aich  his  author  wrote, 

rds  have  different  meanings  in  different  ai 
.:.i       :..::-    \:':    ::.  -..;. .-..  .';/    .::.;:;:;    ;.y    -.;.•_ 

rcomstances  of 
a  local  and  temporary  natu 

229.  Role  6th.    The  mind  of  the  interpreter 
should  be  whoL  from  all  antecedent  1 

in  favour  of  a:  .em,  doctrine,  or  creed, 


RULES    OF    INTERPRETATION.  165 

which  might    influence   his   judgment,  in  the 
interpretation  he  is  about  to  make. 

JJO.  Rule  7th.  In  making  the  interpretation 
of  a  document,  the  subject  and  predict 

ch  proposition  should    be  carefully  distin- 
guished;   the  various  sentences   and   clau 
should    be    construed    in    reference    to    each 
other ;   and  the  resulting  of  all  the  parts 

should  be  connected  and  consistent. 

231.  Rule  8th.  Words,  which  admit  of 
different*  senses,  should  be  taken  in  their  most 
common  and  obvious  meaning,  unless  such  a 
construction  lead  to  absurd  consequences,  or 
be  inconsistent  with  the  known  intention  of 
the  writer. 

-  2.  Rule  9th.  When  any  word  or  expres- 
sion is  ambiguous,  and  may,  consistently  with 
common  use,  be  taken  in  different  senses,  it 
must  be  taken  in  that  sense,  which  is  agreeable 
to  the  subject,  of  which  the  writer  was  treat- 
ing. 

-13.  Rule  10th.  Doubtful  words  and  phra 
must  always  be  construed  in  such  a  sense 
will  make  them  produce  some  effect  ;  and  not 
in  such  a  sense  as  will  render    them  wholly 
nugatory. 


i 


166  RULES    OF    INTERPRETATION. 

234.  Rule  11  A.  Violations  of  the  rules  of 
grammar  da  not  vitiate  a  writing,  in  which  the 
sense  is  distinctly  expressed.  When  a  pas- 
sage is  imperfect,  or  unintelligible,  the  inter- 
preter is  at  liberty  to  supply  such  words,  as 
are  manifestly  necessary  to  render  its  sense 
complete.  But  he  is  not  allowed,  in  a  sim- 
ilar case,  to  expunge  certain  words  from  the 
text,  in  order  to  give  an  intelligible  meaning 
to  those  that  remain. 

235.  Rule  12th.  When  there  are  no  special 
reasons  for  the  contrary,  words  should  be  con- 
strued in  their  literal,  rather  than  in  their  fio-- 
urative  sense  ;  relative  words  should  be  refer- 
red to  the  nearest,  rather  than  to  a  remote 
antecedent ;  and  words,  which  are  capable  of 
being  understood  in  either,  should  be  taken  in 
their  generick,  rather  than  in  their  specifick 
sense. 

236.  Rule  13th.  However  general  may  be 
the  words,  in  which  a  covenant  is  expressed,  it 
comprehends  those  things,  only,  on  which  it 
appears  the  parties  intended  to  contract,  and 
not  those,  which  they  had  not  in  view.  But 
when  the  object  of  the  covenant  is  an  univer- 
sality of  things,  it  comprehends  all  the  parti cu- 


RULES    OF    IN 


It)  7 
J) 

universality, 
had     no 


lar    things,  which  comp 
even    those,    of   which   the 
knowledge. 

237.  Rule  14th.  Whatever  is  ohscure  or 
doubtful  in  a  covenant  should  be  interpreted 
by  the  intention  of  the  parties.  If  the  inten- 
tion of  the  parties  does  not  appear  from  the 
words  of  the  covenant,  it  should  be  inferred 
from  the  existing  customs  and  usages  of  the 
place,  in  which  it  was  made.  If  the  words  of 
a  covenant  contradict  the  well  known  intention 
of  the  parties,  this  intention  must  be  regarded 
rather  than  the  words.* 

238.  Rule  15th.  When  former  interpreters 
are  appealed  to,  in  order  to  establish  the  sense 
of  an  ancient  writing,  those,  cceteris  paribus, 
should  be  preferred,  who  were  nearest  the  au- 
thor, in  time  or  place,  as  his  children,  pupils, 
correspondents,  or  countrymen  ;  and  who  had, 
therefore,  better  advantages  for  knowing  his 
mind,  than  more  distant  commentators. 

*  Sarti,  Dialect.  Instit.  Kirwan,  Logick.  Le  Clerc,  Ars  Critica. 
Vattel,  Law  of  Nations.  Piutherforth,  Lectures  on  Grotius.  Gilbert, 
Law  of  Evidence.    Pothier  on  Obligations.    Domat  on  the  Civil  Law. 


168  CONCLUDING    REMARKS. 

CONCLUDING  REMARKS. 

In  the  preceding  summary,  an  attempt  has 
been  made  to  state  and  explain  those  rules  of 
intellectual  discipline,  which  may  guide  and 
improve  the  reasoning  faculties.  As  the  work 
is  intended  to  be  strictly  elementary,  general 
principles  only  have  been  given,  with  such  plain 
examples,  as  might  limit  and  illustrate  their 
meaning.  The  following  remarks  are  subjoin- 
ed for  the  use  of  those,  who  may  wish  to  ex- 
tend their  inquiries  on  the  subject  of  logick, 
and  the  philosophy  of  the  human  mind. 

Dr.  Reid's  analysis  of  Aristotle's  Logick 
contains  a  brief  but  comprehensive  exposition 
of  the  syllogistick  system.  A  more  full  ac- 
count of  the  categories,  together  with  the  vari- 
ous laws  of  syllogistick  reasoning,  may  be 
found  in  the  logical  treatises  of  Burgersdicius 
and  of  Le  Clerc. 

Of  modern  systems  of  logick,  those  of  Watts 
and  of  Duncan  have  been  most  approved.  A 
more  recent  and  valuable  treatise,  than  either 
of  these,  is  that  of  Kirwan. 

Tt  is  essential  to  accurate  reasoning  to  dis- 
tinguish those  first  principles  of  human  knowl- 


CONCLUDING    REMARKS.  169 

edge,  which  must  be  taken  for  granted,  from 
those  propositions,  which  require  proof.  On 
this  subject  the  treatise  of  Father  Buffier,  en- 
titled First  Truths,  Bcattie's  Essay  on  Truth, 
and  Condillac  on  the  Origin  of  Knowledge, 
are  valuable  sources  of  information. 

The  Novum  Organum  of  Lord  Bacon  con- 
tains  in  a  small  compass  those  rules  of  induc- 
tive logick,  which  have  been  followed  with  the 
happiest  success,  both  in  physical  researches, 
and  in  the  philosophy  of  the  mind. 

On  true  subject  of  moral  reasoning,  important 
information  may  be  derived  from  Gambier's 
Introduction  to  Moral  Evidence,  and  from  the 
first  book  of  Campbell's  Philosophy  of  Rhet- 
orick. 

For  the  general  direction  of  the  mind,  in  its 
researches  after  truth,  rules  of  a  more  practi- 
cal nature  may  be  found  in  Locke's  Conduct 
of  the  Understanding  and  Watts  on  the  Im- 
provement  of  the  Mind. 

The  study  of  those  authors,  who  reason 
clearly  and  accurately,  is  one  of  the  best 
methods  of  improving  the  reasoning  powers. 
For  this  purpose,  Berkeley  on  the  Principles  of 
Human  Knowledge,  Wollaston  on  the  Religion 
15 


170  CONCLUDING    REMARKS. 

of  Nature,  and  Baxter  on  the  Soul,  may  be 
read  with  great  advantage.  The  catalogue 
might  easily  be  extended  if  it  were  thought 
necessary.  It  will  be  concluded  by  referring 
the  student  to  the  metaphysical  writings  of 
Locke,  Reid,  Stewart,  and  Brown.  They  may 
be  consulted  with  great  benefit,  on  each  of  the 
subjects  above  mentioned  ;  and  may  be  said 
to  comprise  in  themselves  a  complete  system 
of  intellectual  philosophy. 

But  the  student  should  remember,  that  nei- 
ther learning  the  best  rules,  nor  reading  the  best 
models,  can  supersede  the  necessity  of  intent 
and  continued  reflection.  He  should  dwell  on 
the  operations  of  his  own  mind,  and  mark  the 
difficulties,  which  prevent  his  arriving  at  clear 
conclusions  ;  whether  they  arise  from  misap- 
prehension of  the  subject,  from  the  ambiguity 
of  language,  from  weakness  in  the  power  of 
attention,  or  from  the  biases  of  association. 
He  will  thus  insensibly  form  a  logick  for 
himself,  which,  while  it  embraces  the  rules, 
common  to  all  minds,  will  be  peculiarly  adapted 
to  the  improvement  of  his  own. 


NOTES    AND    ILLUSTRATIONS. 


Note  A,  page  17. 

I  have  used  reflection  and  consciousness  as  synony- 
mous terms,  and  they  are  so  used  by  eminent  writers  on 
pneumatology.  Some,  however,  have  considered  them  as 
denoting  operations  specifically  different.  Dr.  Reid  says, 
"  reflection  ought  to  be  distinguished  from  consciousness, 
with  which  it  is  too  often  confounded,  even  by  Mr.  Locke. 
All  men  are  conscious  of  the  operations  of  their  own 
minds,  at  all  times  while  they  are  awake,  but  there  are 
few  who  reflect  on  them,  or  make  them  the  objects  of 
their  thought.  Though  the  mind  is  conscious  of  its 
operations,  it  does  not  attend  to  them  ;  its  attention  is 
turned  solely  to  the  external  objects,  about  which  those 
operations  are  employed."*  In  another  place  he  says, 
that  "  attention  to  things  external  is  properly  called  ob- 
servation^ and  attention  to  the  subjects  of  our  conscious- 
ness, reflection."  This  definition  of  reflection  is  substan- 
tially the  same  with  that  of  Mr.  Locke,  which  I  have 
used. 

The  foregoing  passage  from  Dr.  Reid  points  out  a  dif- 
ference in  degree,  rather  than  in  kind,  between  conscious- 
ness and  reflection.     It  is  true  that  the  bulk  of  mankind 

*  Intellectual  Powers,  Essay  I. 


172  NOTES. 

pay  very  little  attention  to  their  mental  operations.  But, 
without  some  degree  of  attention,  they  would  have  no 
consciousness  of  them  whatever ;  and  so  far  as  they  do 
attend  to  them,  so  far,  according  to  Dr.  Reid's  own  ac- 
count, they  reflect. 

The  only  way,  by  which  the  phenomena  of  the  mind 
can  be  investigated,  is  by  attending  to  its  successive 
changes  and  operations,  as  they  are  passing  ;  and  this 
reflex  act  of  attention  is  nothing  more  than  an  effort  of 
the  mind  to  increase  or  prolong  the  consciousness  of  its 
own  acts.  Reflection  on  any  operation  of  the  mind  pre- 
supposes the  actual  existence  of  that  operation.  It  may 
be  examined  afterwards  by  the  assistance  of  memory,  but 
this  subsequent  examination  cannot  be  denominated  re- 
flection, agreeably  to  the  strict  sense  of  that  word.  Are 
we  then  to  believe,  that  reflection  and  consciousness 
are  two  distinct  simultaneous  efforts  ;  and  each  of  them 
different  from  the  operation,  which  the  mind  is  carrying 
on  at  the  same  time  ?  This  would  oblige  us  to  consider 
the  mind,  not  as  simple,  but  as  a  complication  of  different 
powers  or.  agents,  one  of  which  may  be  employed  in 
watching  the  operations  of  another,  while  its  own  acts  are 
examined  by  a  third. 

Dr.  Reid  defines  reflection,  "  attention  to  the  subjects 
of  our  consciousness."  By  this  expression  he  evidently 
supposes  consciousness  and  the  subjects  of  consciousness 
to  be  different  things.  But  the  mind  can  be  conscious 
only  of  what  passes  within  itself.  Consciousness,  then, 
according  to  him,  means  the  notice,  which  the  mind  takes 
of  its  own  operations.  Now,  as  he  places  reflection  in 
attention    to   the    subjects    of  our   consciousness,    and    it 


NOTES.  173 

appears  manifest,  that  by  the  subjects  of  consciousness 
he  means  nothing  else  than  the  operations  of  the  mind, 
it  follows,  even  from  his  own  statement,  that  these  terms 
are  but  different  names  for  the  same  thing. 

In  common  use  there  seems  to  be  a  slight  difference 
in  the  import  of  these  terms.  By  consciousness  is  com- 
monly understood  barely  the  mind's  notice  or  perception 
of  its  own  acts  and  modes  of  existence.  But  reflection 
is  usually  employed  to  express  some  degree  of  voluntary 
attention  to  the  phenomena  of  the  mind,  in  order  to 
ascertain  the  laws,  by  which  it  is  governed.  As  the  bulk 
of  mankind  have  no  curiosity  for  such  speculations,  they 
have  been  said  rarely,  if  ever  to  reflect. 


NoteB,  page  121. 

Logicians  have,  from  the  earliest  period,  denominated 
the  predicate  of  the  conclusion  the  major  term,  and  its 
subject,  the  minor.  The  only  reason,  assigned  for  doing 
this,  is,  that  the  predicate  of  a  proposition  has  a  wider 
extension  than  the  subject.  But  this  is  not  a  suffi- 
cient reason  for  calling  it  the  major  term,  since,  in  all  our 
affirmations  and  negations,  we  are  invariably  governed 
by  the  comprehension  of  terms,  without  the  slightest  re- 
gard to  their  extension.  We  assert  the  more  general  of 
'the  less  general,  for  this  manifest  reason,  that  the  former 
is  a  part  of  the  latter.  We  predicate  the  genus  of  the 
species,  but  not  the  species  of  the  genus.  The  predicate 
of  a  proposition  is  only  an  attribute  of  the  subject  ;  and 
15* 


174  NOTES. 

in  this  light  it  must  be  viewed,  in  order  to  render  the 
proposition  true.  When,  for  example,  we  affirm  that 
saffron  is  }'ellow,  we  refer  a  single  property  to  a  subject, 
in  which  it  is  known  to  coexist  with  several  other  prop- 
erties. In  doing  this,  we  are  guided  by  our  knowledge 
of  that  plant  without  inquiring  what  other  bodies  there 
are  in  existence,  which  have  a  yellow  colour.  And  we 
proceed  in  the  same  way,  when  the  predicate  has  no 
greater  extension  than  the  subject,  as  when  we  affirm  that 
iron  is  susceptible  of  magnetical  attraction. 

In  passing  fiom  one  rank  of  beings  to  another,  in  the 
order  of  their  classification,  we  observe  that  each  supe- 
rior class  stands  in  the  next  below  it.  Thus  we  may  say 
a  mastiff  is  a  dogy  a  dog  is  an  animal,  and  an  animal  is  a 
being,  that  has  life,  sense,  &c.  It  is  obvious  that  the  first 
subject  contains  each  of  the  predicates  that  follow. 

As,  in  an  act  of  judgment,  one  thing  is  perceived  to  be 
contained  in  another,  so,  in  syllogistick  reasoning,  one 
proposition  is  shown  to  be  contained  in  another,  that  in 
a  third,  and  so  on.  This  process  has  been  aptly  illus- 
trated by  a  collection  of  boxes  of  different  sizes,  placed 
one  in  another.  In  such  a  nest  of  boxes,  it  would  be 
natural  to  say  of  that  which  was  placed  first,  and  contain- 
ed all  the  rest,  that  it  was  the  largest  box,  and  of  that, 
which  was  in  the  centre,  and  had  no  other  in  it,"  that  it 
was  the  least  box.  But,  in  giving  names  to  the  three 
terms  of  a  syllogism,  this  rule  of  common  sense  has  been 
violated.  The  less  is  made  to  contain  the  greater.  The 
predicate  of  the  conclusion,  which  is  contained  in  each 
of  the  other  two,  is  called  the  major  term,  and  the  sub- 


NOTES.  175 

ject  of  the  conclusion  which  contains  both  the  others,  is 
called  the  minor  term. 


Note  C,  page  122. 

This  is  true  in  that  arrangement  of  parts,  which  renders 
the  syllogism  (he  most  simple  and  the  most  perfect ;  though 
it  will  not  hold  in  all  those  technical  forms,  in  which  it  has 
been  expressed. 

It  may  not  be  deemed  wholly  impertinent  in  this  place 
to  give  a  brief  description  of  that  celebrated  doctrine  of 
modes  and  figures,  in  which  simple  syllogisms  are  involv- 
ed, in  the  ancient  books  of  logick.  By  the  mode  of  a 
syllogism  is  meant  the  designation  of  the  quantity  and 
quality  of  its  propositions.  By  figure  is  meant  the 
situation  of  the  middle  term  with  respect  to  the  major 
and  minor  terms.  As  the  middle  term  occurs  in  each 
of  the  premises,  it  is  susceptible  of  four  different  positions 
in  relation  to  the  extremes.  Hence  four  figures  have 
been  invented.  In  the  first,  the  middle  term  is  the  sub- 
ject of  the  major  proposition,  and  the  predicate  of  the 
minor.  In  the  second,  it  is  the  predicate,  and  in  the 
third,  the  subject,  of  both  the  premises.  In  the  fourth,  it 
is  the  predicate  of  the  major  premise,  and  the  subject  of 
the  minor. 

Each  of  the  four  figures  has  several  modes,  which  are 
designated  by  the  vowels  A,  E,  I,  0  ;  characters,  em- 
ployed by  logicians  to  denote  the  quantity  and  quality 
of  propositions.     A,  placed  before  a  proposition,  denotes 


176  NOTES. 

that  it  is  an  universal  affirmative  ;  E  denotes  an  universal 
negative  ;  I,  a  particular  affirmative  ;  and  O,  a  particular 
negative.  To  assist  the  memory,  the  following  couplet 
was  contrived  : 

Asserit  A,  negat  E,  verum  generaliter  ambae. 
Asserit  I,  negat  O,  sed  particularity  ambo. 

As  all  the  possible  combinations  of  three  of  these  four 
letters,  in  three  propositions,  amount  to  sixty-four,  this 
number  of  modes  might  be  formed.  But,  of  these,  fifty- 
three  are  excluded  by  certain  established  rules,  and  one 
rejected,  as  useless  ;  leaving  only  ten,  that  are  considered 
as  legitimate.  Several  of  these  are  repeated  in  different 
figures,  so  as  to  make,  in  the  whole,  nineteen  conclusive 
modes.  Each  mode  is  furnished  with  an  appropriate 
name,  consisting  of  three  syllables,  and  containing  three 
of  the  vowels  before  named.  The  three  syllables  of  the 
mode  are  placed  before  the  propositions  of  the  syllogism, 
in  order  that  the  vowel  letter,  which  alone  is  regarded, 
may  indicate  the  quantity  and  quality  of  the  proposition, 
before  which  it  stands. 

To  the  first  figure  are  given  four  modes ;  which  are 
denominated  Barbara,  Celarent,  Darii,  Ferio.  The  second 
figure  has  likewise  four  modes,  namely,  Ccesare,  Cames- 
tres,  Festino,  Baroco.  The  third  has  six  modes,  Darapti, 
Felapton,  Disamis,  Datisi,  Bocardo,  Ferison.  The  fourth 
has  five  modes,  Bamarip,  Camenes,  Dimatis,  Festapo, 
Fresison. 


NOTES.    N^  177 


177 


These  barbarous  words  have  been  thus  formed  into  hex- 
ameter verses  : 

Barbara,  Celarent,  Darii,  Ferio  quocpie,  primse. 
Caesare,  Camestres,  Festino,  Baroco,  secundac. 
:i  Darapti  sibi  vindicat  atque  Felapton  ; 
Disamis,  Datisi,  Bocardo,  Ferison. 

Camenes,  Dimatis,  Festapo,  Fresison. 


EXAMPLES. 

-lire    First. 

o 

Bar-  Every  animal  has  sensation; 

Ba-     Every  man  is  an  animal ; 

Ha.     Terefore  every  man  has  sensation. 

Ce-     No  opinions,  hurtful  to  the  morals  of  society, 

should  be  embraced  ; 
La-     Atheistical  sentiments  are  hurtful  to  the  morals 

of  society  ; 
Rent.  Therefore  atheistical  sentiments  should  not  be 

embraced. 

Da-    All  good  men  love  peace  ; 

Ri-      Some  statesmen  are  good  men  ; 

I.        Therefore  some  statesmen  love  peace. 

Ft-     No  man  of  dissolute  habits  is  a  safe  companion  ; 
Ri-      Some  men   of  learning  are  dissolute  in  their 

habits  ; 
O.       Therefore  some  men  of  learning  are  not  safe 

companions. 


178  NOTES. 


Figure    Second. 

Ca-    Every  virtuous  man  is  fit  to  be  believed  ; 

Mes-  No  liar  is  fit  to  be  believed  ; 

Tres.  Therefore  no  liar  is  a  virtuous  man. 

Ba-     Every  true  patriot  tries  to  promote  the  publick 

good; 
Ro-     Some  men  in  high  stations  do  not  try  to  promote 

the  publick  good ; 
Co.     Therefore  some  men  in  high  stations  are  not 

true  patriots. 


Figure    Third. 

Da-    All  good  Christians  will  be  saved ; 

Rap-  All  good  Christians  have  sinned  ; 

Ti.      Therefore  some,  who  have  sinned,  will  be  saved. 


Examples  of  the  other  modes  may  readily  be  formed. 


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